feat: IONConnect DB conversation infrastructure

[ice-damocles]

Description

Adds

• IONDatabaseNotifier to proxy DB from direct interaction
• General Event messages insert
• One-to-one conversation DB logic: init of the conversation, new messages, last message
• Group conversations DB logic: init of the conversation, new messages, change of subject, change of participants amount
• Test event messages mocks
• Changes to conversation provider: mocks are removed

Type of Change

• Bug fix
• New feature
• Breaking change
• Refactoring
• Documentation
• Chore

[ice-orion]

In my understanding empty content can also mean that:

1. This is the first message of a conversation (doesn't matter 1v1 or group)
2. This is the event that changes the group participants
3. This is the event that changes the group subject

We need to process the event first before generating a new uuid for it and inserting to the conversations table.

So in my understanding it should be like:

Try to find a conversation that the message belongs to by pubkeys fingerprint (sorted p tags + pubkey)
      * If not found
            *  If this is a "service" message (no content) ->  try to find by the subject
                     * if found -> insert with the found conversation id (meaning the participants have changed)
                     * if not found -> generate uuid, insert
              * If this is a regular message -> throw exception
       * If found -> insert with the found conversation id

[ice-damocles]

Will fix and write unit tests for it

[ice-ares]

@ice-orion empty content also means u change the group picture