[Security Solutions][Detection Engine] Migrates exception lists to sa…

…ved object references (Part 2) (#108291) (#108991)

## Summary

This is part 2 to addressing the issue seen here: #101975 (Part 1 #107064)

This adds the alerting migration scripts and unit tests for exception list containers on Kibana startup for `7.15.0`

We only migrate if we find these conditions and cases:
  - `exceptionLists` are an `array` and not `null`, `undefined`, or malformed data.
  - The exceptionList item is an `object` and its `id` is a `string` and not `null`, `undefined`, or malformed data
  - The existing references do not already have an exceptionItem reference already found within it.

We migrate on the common use case
  - The saved object references do not exist but we have exceptionList items with the id's to create the saved object references, 👍 so we migrate.
  - The alert contains no exception list items, in which case we have nothing to migrate 

We do these additional (mis-use) cases and steps as well. These should _NOT_ be common things that happen but we safe guard for them here:
  - If the migration is run twice we are idempotent and do _NOT_ add duplicates list items or remove items.
  - If the migration was partially successful but re-run a second time, we only add what is missing. Again no duplicates or removed items should occur.
  - If the `exceptionLists` contains invalid data shape or not enough information to migrate, we filter it out and ignore it
  - If the saved object references already exists and contains a different or foreign value, we will retain the foreign reference(s) and still migrate.  
 

## Manual testing 
There are unit tests but for any manual testing or verification you can do the following:

Create a few alerts through the `security_solution` application with exception lists
<img width="1775" alt="Screen Shot 2021-08-11 at 5 42 31 PM" src="https://user-images.githubusercontent.com/1151048/129117377-61b17fcf-ad01-4405-bbfe-42d97a6f7654.png">

Use the dev tools to de-migrate as well as to test end to end like so:

```json
# First get an "_id" with an exceptions list like below.  Mine I found was: "alert:38482620-ef1b-11eb-ad71-7de7959be71c":
GET .kibana/_search
{
  "query": {
    "terms": {
      "alert.alertTypeId": [
        "siem.signals"
      ]
    }
  },
  "size": 10000
}
``` 

With Kibana running downgrade and remove the references as a test:

```json
# Set saved object array references as empty arrays and set our migration version to be 7.14.0 
POST .kibana/_update/alert:38482620-ef1b-11eb-ad71-7de7959be71c
{
  "script" : {
    "source": """
    ctx._source.migrationVersion.alert = "7.14.0";
    ctx._source.references = []
    """,
    "lang": "painless"
  }
}

# Double check the references is empty and the version is 7.14.0
GET .kibana/_doc/alert:38482620-ef1b-11eb-ad71-7de7959be71c
```

Reload the alert in the `security_solution` and notice you get these errors until you restart Kibana to cause a migration moving forward

```sh
server    log   [17:35:16.914] [error][plugins][securitySolution] The saved object references were not found for our exception list when we were expecting to find it. Kibana migrations might not have run correctly or someone might have removed the saved object references manually. Returning the last known good exception list id which might not work. exceptionItem with its id being returned is: {"list_id":"endpoint_list","namespace_type":"agnostic","id":"endpoint_list","type":"endpoint"}
server    log   [17:35:16.914] [error][plugins][securitySolution] Cannot get a saved object reference using an index which is larger than the saved object references. Index is:1 which is larger than the savedObjectReferences:[]
server    log   [17:35:16.915] [error][plugins][securitySolution] The saved object references were not found for our exception list when we were expecting to find it. Kibana migrations might not have run correctly or someone might have removed the saved object references manually. Returning the last known good exception list id which might not work. exceptionItem with its id being returned is: {"list_id":"cd152d0d-3590-4a45-a478-eed04da7936b","namespace_type":"single","id":"50e3bd70-ef1b-11eb-ad71-7de7959be71c","type":"detection"}
server    log   [17:35:16.940] [error][plugins][securitySolution] The saved object references were not found for our exception list when we were expecting to find it. Kibana migrations might not have run correctly or someone might have removed the saved object references manually. Returning the last known good exception list id which might not work. exceptionItem with its id being returned is: {"list_id":"endpoint_list","namespace_type":"agnostic","id":"endpoint_list","type":"endpoint"}
server    log   [17:35:16.940] [error][plugins][securitySolution] Cannot get a saved object reference using an index which is larger than the saved object references. Index is:1 which is larger than the savedObjectReferences:[]
server    log   [17:35:16.940] [error][plugins][securitySolution] The saved object references were not found for our exception list when we were expecting to find it. Kibana migrations might not have run correctly or someone might have removed the saved object references manually. Returning the last known good exception list id which might not work. exceptionItem with its id being returned is: {"list_id":"cd152d0d-3590-4a45-a478-eed04da7936b","namespace_type":"single","id":"50e3bd70-ef1b-11eb-ad71-7de7959be71c","type":"detection"}
```

Restart Kibana and you should no longer have errors in the Kibana console.

If you do this query in dev tools

```json
# Check that the `migrationVersion` is `7.15.0` and that we have a `references` array filled out with the correct structure
GET .kibana/_doc/alert:38482620-ef1b-11eb-ad71-7de7959be71c
```

You should notice that you now have a `references` array filled out:
```json
"references" : 
[
  {
    "name" : "param:exceptionsList_0",
    "id" : "endpoint_list",
    "type" : "exception-list-agnostic"
  },
  {
    "name" : "param:exceptionsList_1",
    "id" : "50e3bd70-ef1b-11eb-ad71-7de7959be71c",
    "type" : "exception-list"
  }
],
  "migrationVersion" : {
    "alert" : "7.15.0"
  }
```

For testing [idempotentence](https://en.wikipedia.org/wiki/Idempotence) 

Run just this to downgrade and restart Kibana and you should notice on a GET that we do not have anything extra in the references array:

```json
# Set our migration version to be 7.14.0 only
POST .kibana/_update/alert:38482620-ef1b-11eb-ad71-7de7959be71c
{
  "script" : {
    "source": """
    ctx._source.migrationVersion.alert = "7.14.0";
    """,
    "lang": "painless"
  }
}

# Double check the `references` is still there, and we do not get errors or changes to `references` after we restart Kibana
GET .kibana/_doc/alert:38482620-ef1b-11eb-ad71-7de7959be71c
```

For testing foreign keys:

```json
# Set saved object array references to foreign keys and set our migration version to be 7.14.0 
POST .kibana/_update/alert:38482620-ef1b-11eb-ad71-7de7959be71c
{
  "script" : {
    "source": """
    ctx._source.migrationVersion.alert = "7.14.0";
    ctx._source.references = [["name" : "foreign", "id" : "123", "type" : "some-type"]];
    """,
    "lang": "painless"
  }
}
```

Restart, ensure no errors in Kibana console and do a get call to ensure we have the foreign mixed with valid values:

```json
GET .kibana/_doc/alert:38482620-ef1b-11eb-ad71-7de7959be71c
```

Should return this data:

```json
"type" : "alert",
"references" : 
[
  {
    "name" : "foreign",
    "id" : "123",
    "type" : "some-type"
  },
  {
    "name" : "param:exceptionsList_0",
    "id" : "endpoint_list",
    "type" : "exception-list-agnostic"
  },
  {
    "name" : "param:exceptionsList_1",
    "id" : "50e3bd70-ef1b-11eb-ad71-7de7959be71c",
    "type" : "exception-list"
  }
]
```

### Checklist

- [x] [Unit or functional tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html) were updated or added to match the most common scenarios

Co-authored-by: Frank Hassanabad <[email protected]>