[Meta] Security Analytics Custom Log Types support

[petardz]

linked issue #447

Tasks:

• 1. Define new LogType(JSON) structure which holds log type's name, description and field mappings. For pre-packaged rules there should be set of files(1 file per log type) stored on disk. On Security Analytics startup, load these files into system index: .opensearch-sap-log-types-config.

• 2. User-defined(Custom) log types. Provide CRUD API for user to define its own custom log type. Custom log type will be defined by new LogType structure defined in first task and stored in .opensearch-sap-log-types-config index. Replace DetectorType enum with class which loads detector types(log types) from .opensearch-sap-log-types-config.

• 3. Modify existing Mappings APIs to utilize new JSON structure defined in first task, instead of mapping.json files.

• 4. Implement auto-detection of mapping schema(ECS, OCSF) used in log index.

[getsaurabh02]

We already merged the OCSF integration as part of #447
We will focus on Custom Log Type in 2.10

[sandervandegeijn]

Full ECS support would be nice as well. When trying to load the whole ECS schema component templates a couple of weeks ago Opensearch didn't support a couple of field types.

[DarshitChanpura]

@getsaurabh02 Should this be marked for 2.11?

[amsiglan]

Added support for custom log types in 2.10