Rewrite rooms data structure

Checklist

[X] The same feedback was not posted yet.
[X] This is not a suggestion for the moderation team.
[X] All info applicable to the issue has been attached.

Is your feature request related to a problem? Please describe.

For Revolt/Guilded Support, rooms need to be synced every time the Revolt bot boots. So when a room is created after the support Plugin was last loaded, this room will not sync.

Describe the solution you'd like

Change structure like this:

"rooms": {
  "main": {
    "discord": {
      "123456789012345678": {}
    },
    "revolt": {
      "01HQEBPBRCTYY63XGXK8GA36PS": {}
    }
  }
}

Describe alternatives you've considered

Adding an auto-sync system to Revolt Support whenever an unknown room is created, but organizing the structure like this would probably be better, especially once native community-maintained platform support drops.

Additional context

UnifierHQ / unifier

Rewrite rooms data structure #150