Codechange: Pass face index as font os_handle for FreeType fonts. (#11073)

This allows fallback font detection to test the specific face within the
font rather instead of only the first.

Codechange: Remove Freetype bits on Win32/OSX. (#10960)

These platforms have their own specific font rendering.

Fix: Wayland crash on startup due to Pango also using FontConfig (#10916)

Basically, we haven't been a good neighbour. Turns out you shouldn't
actually call FcFini when you are done, as some library might still
want to use FontConfig. And they use a shared instance for their
administration.

The idea is that you call FcInit once, and use FcConfigReference
after that to get an instance, you can release. This entry is
ref-counted, and things happen automatically based on that.

At least, I think.

Fix: Ask FontConfig for the face index when opening fonts. (#10878)

This allows selection of the correct face in truetype fonts containing
multiple faces.

Codechange: fmt (and std::format) do explicitly not support enums out-of-the-box

That it works for the version we have packaged it pure coincidence, as that is
one of the few versions that due to a bug allow it. So add the appropriate
template specialisations to support it out-of-the-box within OpenTTD.

Change: Rename some freetype things to fontcache.

The font cache supports more than just FreeType as a font provider, but still used freetype in some naming.

This now uses more suitable terms.