Decentralized moderation should be able to be enabled all at once for every protected room

We should turn the roomID on the `!mjolnir rooms setup reporting` command optional.

Start by locating the implementation and argument parsing for the `!mjolnir rooms setup reporting` command. Make `roomID` optional so the command can be invoked without it to enable decentralized moderation for every protected room, then run the command's existing tests or verification flow if available.

Written by the indexing model from the issue text.