Documentation cleanup

[akaszynski]

This PR cleans up the documentation by:

• Using internal links for any method or class references
• Adds external links for various linked projects.
• Refactor API documentation to make it easier to navigate.
• Move Query class documentation to the API section.

Also edits the CI with:

• Adding development doc nightly build step (will be deployed to dev.mapdldocs.pyansys.com after merge).
• Removing the full API build step for the docbuild. There's no reason to do a full doc-build for each PR, it's sufficient to build nightly and run a docbuild smoketest.

[jgd10]

LGTM. I saw a couple of spelling mistakes, which I've already corrected and also made a suggestion about non_interactive, but that might be worth going in a separate issue rather than being a focus of this PR.

[jgd10]

Would this be better as a function? I think it's already a property, so this might be a breaking change, but seeing with for a property looks quite odd to me, maybe it's also the lack of an as thing as well!

[akaszynski]

I agree that it's a bit odd, I was trying for simplicity here:

with mapdl.non_interactive:
   mapdl.prep7()
   ...

vs a more standard approach:

with mapdl.non_interactive() as ni:
    ni.prep7()
    ...

However, the former approach is non-standard and I'll agree that it has side effects (since it's effectively changing the state of the mapdl object). Let's consider changing this in a future PR.