[mujs] Missing fixes

[dg0yt]

Follow-up from #29543:

• Fix name of unofficial cmake config.
• Fix version information of cmake config.
• Add and document official usage: mujs.pc (as in upstream makefile)
• Link libm when available (as in upstream makefile)
• Enable shared linkage for non-windows (as in upstream makefile)
• Cleanup

Extras remarks (not adressed):

• The unofficial cmake config is fairly obsolete with the official pc file.
• The official downloads are at https://mujs.com/downloads/
  There is also a GH organization matching the company's name, but it seems less popular:
  https://github.com/ArtifexSoftware/mujs
• The licensing might be more complex:
  https://tracker.debian.org/media/packages/m/mujs/copyright-1.3.2-1

---

• Changes comply with the maintainer guide
• SHA512s are updated for each updated download
• The "supports" clause reflects platforms that may be fixed by this new version
• Any fixed CI baseline entries are removed from that file.
• Any patches that are no longer applied are deleted from the port's directory.
• The version database is fixed by rerunning ./vcpkg x-add-version --all and committing the result.
• Only one version is added to each modified port's versions file.

[JavierMatosD]

Thanks for the fix @dg0yt. This looks much better.

[as-shura]

Why all those changes I was not aware of? Are those new requirements for all future ports?

[dg0yt]

Why all those changes I was not aware of? Are those new requirements for all future ports?

Some changes are identical to what I requested for mupdf, your other PR.
Some changes are for old port shortcomings with regard to upstream.
Some changes are pure cleanup.
It is all based on the current maintainer guidelines.
To discuss all those issues, it needs fair time for review and constructive communication.