Create shared start/stop scripts for better extensibility

[glorpen]

This PR replaces current docker-runscript with scripts for service start and stop actions - used by systems with and without systemd.
There is not much added functionality for end-user, just singular new parameter - after_create in docker::run. In my current use case it will allow to easily add connecting container to multiple networks (since docker create is now always used).
Additionally this PR opens a way to add handling for named user/group from host system, eg. --user $(id -u user):$(id -g group). (PR's for both will come later)

Currently the first one is possible by overusing extra_systemd_parameters parameter and second one is not even possible because of systemd $() handling.

Main changes:

• no ExecStartPre/ExecStop(Post) in systemd service
• shared logic for start/stop actions (shell script), based on existing upstart code
• docker create is now always used in init scripts, no docker run

[davejrt]

@glorpen can you please resolve the merge conflict here and we can look at getting this merged for the next release.

[davejrt]

Can you please remove all detach params and documentation pertaining to this param, as it's being removed.

[glorpen]

@davejrt Done, I hope I've catched all run::detach uses.

[davejrt]

LGTM

[davejrt]

@glorpen looks like this is breaking on systems using upstart. Primarily the -a flag with docker start. Do you want to push a fix, or we'll have to revert the PR so it doesn't break our next release.

[glorpen]

@davejrt hmmm, wouldn't reverting f5de8ac fix it? I didn't noticed it before but $valid_detach is still used in inline script and it should result in absence of -a flag when not on systemd and now it is undef so I guess always systemd behavior.

[davejrt]

I think you're correct, can you revert it on your fork and push that as the commits are squashed on the merge of the PR

[glorpen]

Done

[davejrt]

Do you want to submit the fix as a PR?

[glorpen]

If it is required, I'm fine with you just merging/squashing/etc it.

[glorpen]

@davejrt not sure if repo silence is caused by holidays or not; let me know if you want me to create that PR after all :)

[davejrt]

Happy Holidays, if you could create the PR that would be great