Authority module to provide features for governance including dispatch method on behalf other accounts and schedule dispatchables.

• dispatch_as can dispatch a dispatchable on behalf of other origin.
• schedule_dispatch can schedule a dispatchable to be dispatched at later block.
• fast_track_scheduled_dispatch can fast track a scheduled dispatchable.
• delay_scheduled_dispatch can delay a scheduled dispatchable.
• cancel_scheduled_dispatch can cancel a scheduled dispatchable.