Re-enable `RoomInfoNotableUpdateReason`

We have introduced `RoomInfoNotableUpdateReason` to get finer grained updates from a `RoomInfo`, and to reduce the number of updates for `RoomList`. Turns out, we had to disable it (see https://github.com/matrix-org/matrix-rust-sdk/pull/3728) because a lot of _business rules_ were not clearly defined: the room list was missing updates from `RoomInfo`. We need to restore `RoomInfoNotableUpdateReason`, but first we need to define the _business rules_ exactly.

* https://github.com/matrix-org/matrix-rust-sdk/pull/3680 to make `READ_RECEIPT` an explicit update,
* https://github.com/matrix-org/matrix-rust-sdk/pull/3705 to make `UNREAD_MARKER` an explicit update,
* and so on.

But a lot more are missing, like a new room name, a new room avatar, stuff like that. We need to list them precisely.

cc @manuroe

Start by reviewing the disabled RoomInfoNotableUpdateReason work in PR #3728, then compare PRs #3680 and #3705 for the explicit READ_RECEIPT and UNREAD_MARKER cases. Define the complete business-rule list for RoomInfo updates, including the missing room name and avatar cases, and restore the feature once RoomList no longer misses updates.

Written by the indexing model from the issue text.