Channel (soft) deletion doesn't track the history of the change

[bjester]

Observed behavior

A user deleting their channel, or an admin deleting a channel from the Admin page, does not record the deletion in ChannelHistory. This is because both bypass where that is handled.

Expected behavior

We should track these deletions in the history.

User-facing consequences

We can't audit who deleted a channel

Steps to reproduce the issue

1. Create a channel
2. Delete the channel
3. Query the database for the channel history
4. Observe no deletion action
5. Query the database for deletion or update related change events
6. Observe no corresponding change events

[bjester]

Moving the tracking to the model so it's always called should be most robust. Although, it also worth considering updating how we submit and process the deletion actions since it's currently bypassing our change event architecture, leaving questions of whether a channel deletion is propagated to other clients