Add bash completion for new prune commands

[albers]

This adds bash completion for

• docker system prune
• docker container prune
• docker image prune
• docker volume prune
• docker network prune

Ref: #26108, #27525

[vdemeester]

LGTM 🐶
/cc @AkihiroSuda @thaJeztah @justincormack

[AkihiroSuda]

Tested locally and LGTM

[albers]

@vdemeester Please schedule for 1.13.0

[thaJeztah]

@albers I added the PR's to the milestone. Note that the initial RC for 1.13 will be branched from master, so cherry-picking is only needed for changes after the code freeze (after 1.13.0-rc1 is released)

[albers]

@thaJeztah Thanks!
I took the omnipresence of 1.13.0 labels for a sign that the release branch already exists.

[thaJeztah]

@albers adding the milestones never hurts, I regularly add them also for easier tracking in future :-) (e.g. to find out which release a PR was included in)