Short circuit enqueue directly to workers if there are workers ready to take jobs for queue

[akira]

When feature is enabled, send job directly to workers if they are free and skip redis enqueue / dequeue.

Also add a configuration option: short_circuit_enabled

Acceptance Criteria:

• If there are free workers for the specific queue (depends on concurrency setting)
• If short_circuit_enabled is set to true in config
• Then don't enqueue job to redis, send directly to worker
• Same code path should be used except the enqueue / dequeue
• Stats should still be tracked as usual
• Should still be put in backup queue