Add "once" job runner

[mushkevych]

This Ticket explores support for one-time jobs, such as version upgrader.
There are likely several use-cases:

global_lock=False job

• Such job does not halt other jobs from running
• As such, it can be implemented as freerun job, where trigger_frequency=once (meaning it will be triggered once, 1 minute after the Synergy Scheduler is up and running)

consideration

• The concept of "once-per-release" jobs (a subset of "one-time job") implies that backward-incompatible schema changes will be performed before any new jobs are run
  However, this contradicts with allowing such job to run as freerun

global_lock=True job

• Such job would halt all other jobs from running and only after it has passed
• As such, it needs to be implemented as managed job and blocking any new job trigerring

consideration

• managed jobs would not prevent previously triggered/running jobs from completion on chimera schema (UOW dispatched in queues would either needs to be cleared with potential of loosing state)

cli-only job

• Such job would be triggered manually and can re-use Supervisor fabric

consideration

• This approach will allow for updating schema while Synergy Scheduler and managed jobs are shut down.
• No UI makes it inconvenient for operator to check logs or status of the one-time job