GUI: add “increase time limit” requests to game/draft/sideboarding

Looks like current rollback request dialog, but for time limits. One user makes request, another users must approve it.
* [ ] games: increase priority time by 5 minutes (easy to implement)
* [ ] draft: increase picking limit by 30 seconds (maybe hard to implement, need requests testing in deck editor);
* [ ] sideboarding/construction: increase time limit by 5 minutes (maybe hard to implement, see above);
* [ ] optional: game pause request (same as increase time limit, but increases time for all players);