Add confirmation dialog for room shutdown (in certain cases)

[CrimsonFork]

Problem.

Recently, on a HS I moderate, due to a miscommunication we shut down an official room, because we didn't double-check the internal ID that was provided.

Possible concerns.

In this case it wasn't malice, but I could also imagine it wouldn't be too hard to create hassle that way, e.g. by creating a bunch of rooms on an HS that obviously violate its policy and then, posing as a concerned user, provide a list of internal IDs, while mixing some legitimate ones into the list.

Suggested solution.

It would help if in certain cases Mjolnir asked for a confirmation, first. This could include:

• if an internal ID was given, when the room has a published ID(s)
• the room is created or moderated by a user which is accepted as a moderator/admin by the Mjolnir instance
• the room has the instance's account in it

The relevant information would be provided in the response. Mjolnir could attach a 👎️ reaction to that message to easily abort, and only continue with a manually placed 👍️, the idea being that one doesn't easily misclick to approve it.

Noteworthy considerations.

• Being able to disable the feature as a whole or aspects of it.
• Should this be on by default? (IMO, yes.)
• A method to approve/abort for clients where reacting with an emoji wouldn't typically be easy, e.g. the CLI clients.