Handle/manage lifecycle of stored conversations

[ruKurz]

Once conversations are stored at the Smarti-side, a need arises to manage what's actually being respected for searching related conversations:
Information from particular conversations may become obsolete, some parts may have to be altered or mass-added.

These operations shall happen exclusively at the Smarti-side (without interaction via Rocket.Chat).

• Import conversations (from JSON/XML, Add a web service that provides conversation imports #36)
• Set an expiration date, instantly mark conversations obsolete => not respected in a search (Conversations should have an expiration date #59)
• Author messages of a conversation (with a human friendly UI): Change texts, remove messages, remove attachments (UI for conversation management #33)
• Export conversations (to JSON, XML, UI for conversation management #33)

This implicitly requires a conversation-display UI

Target group

• End-User

Acceptance criteria

• Permission concept is defined (Define and Implement a user authentication model #60)
• A choice about the identity provider has been made (Define and Implement a user authentication model #60)
• User driven management (down voting, Rating historic conversations #58, Add support for message voting #69)

Sub-Issues

• Configuration API for conversation management API for conversation management #32
• Configuration UI for conversation management UI for conversation management #33

[mrsimpson]

It shall be possible to apply mass-changes to conversations. For this, http-PATCH shall be possible.
For illustrative purposes: PATCH to /conversation/?client="myOldClient"

 {
  "client": "myNewClient"
 }

[tkurz]

To be clarified: Which are the service consumer roles. This roles have to be defined, e.g.

• Admin: Can Read/Update/Delete messages for all client / (Mass-) Import messages / Configure Clients
• Client-Editor: Can Read/Update/Delete his own messages
• Autor:

[tkurz]

The concept we will implement is "API-drive" permissions. Thereby a role is defined as a set of API calls the role is able to run.

[ja-fra]

Marking as done - see linked issues for implementation details and progress.