This PR is based on the previous work by @snuggie12 in PR #6825. It adds the command consul intention list to list all available intentions. The list functionality for intentions seems a bit overdue as it's just very handy. The web UI cannot list intentions outside of the default namespace, and using the API is sometimes not the friendliest option. ;)
I cherry picked snuggie12's commits who did most of the heavy lifting (thanks again @snuggie12 for your great work!). The changes in the original commit mostly still worked on the current HEAD. On top of that I added support for namespaces and fixed the docs as they are managed differently today. Also the requested changes related to the "Connect" references in the original PRs have been addressed.
Fixes#5652
Co-authored-by: Matt Hoey <mhoey05@jcu.edu>
