[messaging] Add message deletion during partial sync

[Weiko]

Context

• Rename remaining V2 services.
• Delete messages in DB when gmail history tells us they've been deleted. I removed the logic where we store those in a cache since it's a bit overkill because we don't need to query gmail and can use those ids directly. The strategy is to delete the message channel message association of the current channel, not the message or the thread since they can still be linked to other channels. However, we will need to call the threadCleaner service on the workspace to remove orphan threads/non-associated messages.

Note: deletion for full-sync is a bit tricky because we need the full list of message ids to compare with the DB and make sure we don't over-delete. Currently, to keep memory, we don't have a variable that holds all ids as we flush it after each page. Easier solution would be to wipe everything before each full sync but it's probably not great for the user experience if they are currently manipulating messages since full-sync can happen without a user intervention (if a partial sync fails due to historyId being invalidated by google for some reason)

[charlesBochet]

@Weiko I cannot test the behavior but the code looks good to me. It would be good that @bosiraphael tests it.

Regarding full-sync, can we go over each existing message and query google? If we get 404 we remove?

[bosiraphael]

LGTM, left a comment

[bosiraphael]

Typo GmailFullSynModule