Make bot aware of cross-year spaces and rooms

[kittykat]

The bot should be aware of rooms which persist across conferences and it needs to interact with.

For FOSDEM, we have these rooms in a cross-year space.
The rooms should be added to the new space that the bot creates during setup.

This is low priority for 2022 (we can do this manually) but should be fixed after the conference.

[squahtx]

Apart from the infodesk, FOSDEM has a bunch of rooms like #cafe, #food-trucks, etc.
We could extend the bot config to tell it to add certain pre-existing rooms to the conference space, or subspaces.