Add auto-start-queue as core ghb feature (currently only windows ui feature)

[WillGunn]

Description of the feature or enhancement you'd like to see in HandBrake

Based on what I can see, it looks like only the windows gui supports a startup argument that causes handbrake to automatically start encoding if it loads up with a non-empty queue: https://github.com/search?q=repo%3AHandBrake%2FHandBrake%20auto-start-queue&type=code

I can't seem to find this feature being available in the base handbrake/ghb as I would like to be able to do that from linux (particularly from docker).

What Operating System are you running?

Linux/Docker

What version of HandBrake are you running?

1.6.1

Where did you download HandBrake from?

docker jlesage/handbrake

Activity Log, Crash Log or any other details

No response

[rcrh]

This would be a great addition. My server shuts down my dockers each night to take a back up and then starts them again. I would be great to not loose hours of encoding time every single night.