Custom queue support

[Xieyt]

Tasks

Beta Give feedback

1. Support automatic addition of custom workers when custom queue are defined in common_site_config.json.
2. Reflect changes when supervisor.conf changes detected.
3. Provide sub command group queue/workers for handling custom queue operations.
4. Don't remove default workers.

These commands will be supported by fm queue <command> <sitename>

Beta Give feedback

1. list/info -> info about queue and workers
2. add -> add workers to pre defined queue or new queue and regenerate worker containers.
3. remove -> add workers from custom queue and regenerate worker containers.
4. reset -> regenerate worker containers based on current config.

[Xieyt]

* Support automatic addition of custom workers when custom queue are defined in `common_site_config.json`.
* Reflect changes when supervisor.conf changes detected.
* Don’t remove default workers.

Implemented in #91.