(process) Processes should be possible to run from the command line

[vlofgren]

As far as practical, processes should be possible to run from the command line and not always pull instructions from the control message queue.

This could be done by having e.g.

$ crawler-process auto
$ crawler-process manual /path/to/specs /path/to/data

ProcessService in control-service would need a bit of modification as well to feed the auto command into the execve-array.

...

This is probably relatively simple, but also a good opportunity to look over the highly duplicated code in fetching instructions.