Integrate Supervisor for Efficient Command Management within Containers

[Xieyt]

• Make sure to run only one process in each container. Exception:-> frappe container in dev mode as file watcher(spawned by bench watch) is only required in dev mode
• In previous implementation frappe container was handling 4 process as defined in Procfile and now frappe container will handle 2 process max in dev mode. Introduce containers for those extra processes.
• Use bench provided supervisor.conf for running services using supervisor.
• command to generate supervisor.conf: bench setup supervisor
• Dynamic Workers(Custom queue support) can also be implemeted using this.

[Xieyt]

* Make sure to run only one process in each container. Exception:-> `frappe` container in dev mode as file watcher(spawned by `bench watch`) is only required in dev mode

* In previous implementation `frappe` container was handling 4 process as defined in Procfile and now `frappe` container will handle 2 process max in dev mode. Introduce containers for those extra processes.

* Use bench provided supervisor.conf for running services using supervisor.

* command to generate supervisor.conf: `bench setup supervisor`

Implemented in #91.

* Dynamic Workers(Custom queue support) can also be implemented using this.

This is being worked on in another issue #93.