feat: Allow leader to change beacon duration, and deactivate the beacon.

[Aadeesh11]

Fixes #17 #5 Note: Since the mutation is recently merged in the backend, it has not yet been deployed to the cloud. So to test, fork the backend repo and setup the backend locally, update the .env accordingly, and then test the changes.

[ItsAdityaKSingh]

@Aadeesh11 Could you resolve the conflicts :)

[Aadeesh11]

Resolved :)

[ItsAdityaKSingh]

There are still some conflicts @Aadeesh11 :)

[Aadeesh11]

Again, Resolved @ItsAdityaKSingh :)