Allow rich rules bash command completion

[mailinglists35]

What would you like to be added

bash command completion for adding rich rules.

Why is this needed

to ease day to day command line use of firewall-cmd.

firewall-cmd is very unconfortable to use without bash completion, first because every verb and subject begins with double dash (why oh why!?!), second because without completion you'd have to memorize lots of verbs and subjects.

if for deletion I can simply copy/paste the existing output, for --add-rich-rule='rule [...]' creation is a pain without autocomplete. I sometimes can copy from existing other rich rules but when creating first rule there is nowhere to copy the model from. and when you're in a cold datacenter in front of a cli terminal and no text mode mouse gpm daemon available copy/pasting is even more difficult.