Adds a functional test which parses available RPC commands, generates
the associated bitcoin-cli autcomplete file and checks that the current
autocomplete matches the file
An outdated autcomplete file can be updated using the --overwrite parameter
Co-authored-by: pierrenn <git@pnn.sh>
Github-Pull: #30860
Rebased-From: 7c8b021fee3b528ff28b85ec2e8933ebc5b2b488
