Issue #5603 - Single page documentation

[WalkerWatch]

Issue #5603 Creates single page output for 9.4.x documentation and aligns with 10 and 11 documentation formatting.

[jmcc0nn3ll]

If we are going to wack out the docbook backend entirely we should clear out the xslt files, basically the src/main/docbkx-* directories. Might be good to go through and make sure none of that is referenced but I think that stuff was mostly just syntax highlighter and font type stuff.

[jmcc0nn3ll]

See prior comment.

[sbordet]

I ran the documentation generation, and I get a ton of warnings and errors.

In particular, all source code blocks for XML are broken, so the generated documentation is unreadable.

Remove subs={sub-order} from everywhere, it's now broken, it's unnecessary in most cases, and should be explicitly added only in blocks that require it.

The "parts" use level 0 sections, should be using level 1 (see warning during generation).

There is also a number of invalid cross references that should be fixed.

[jmcc0nn3ll]

As long as this visually looks fine I am good to go with it, it lets us get the updated website leveraging it so we can deploy that going into the 10 and 11 releases. Any content changes we need to make can be done separately.

[WalkerWatch]

@sbordet Any other changes you'd like to see?

[WalkerWatch]

@sbordet Done, not sure how I managed to miss those. CI Building now. Good to go when green?