Allow set room join rule to knock

NeoChat still need to support sending a knock request, and maybe also accepting a knock request.

btw, in nearby code about "Space-only" type:

enabled: room.canSendState("m.room.join_rules") && ["8", "9", "10"].includes(room.version) && false

the && false will result it will be always false. I'm not sure if that's here bc it's still WIP, so I didn't touch that part.