Link to local docs

[edlerd]

Done

• docs are now shipped with lxd, link to the local docs, when server version is bigger than 5.18

QA

1. Run the LXD-UI:
   • On the demo server via the link posted by @webteam-app below. This is only available for PRs created by collaborators of the repo. Ask @lorumic or @edlerd for access.
   • With a local copy of this branch, run as described here.
2. Perform the following QA steps:
   • check documentation links for a lxd backend with a recent version (bigger than 5.18) -- spot checking should be enough and code review that they are unchanged apart from the base url.

[webteam-app]

Demo starting at https://lxd-ui-533.demos.haus

[lorumic]

All good 👍