add bash completion support for pause and unpause

Signed-off-by: Michael Scharf <github@scharf.gr>
Optimize the bash completion even further

The biggest/bestest change here is cutting down on the number of calls to Docker in the filtering helpers (`__docker_containers_running`, etc), especially calls to the really heavy `docker images`.

Signed-off-by: Andrew Page <admwiggin@gmail.com>
Merge pull request #8364 from tianon/bash-completion-filters

Optimize the bash completion even further