Various fixes for using gtk4 as a meson subproject

• Always look for both cmake and pkgconfig names
• Remove redundant, duplicate, harfbuzz check
• Update gitlab.gnome.org SSH server names in wraps
• Stop using fallback: kwarg for deps that don't need it. There will be more fixes incoming later, once PRs/MRs in other projects are merged:
  • sysprof!58 (merged)
  • gdk-pixbuf!148 (merged)
  • World/libcloudproviders!48 (merged) (used old method)
  • https://github.com/ebassi/graphene/pull/255
  • https://github.com/anholt/libepoxy/pull/282
  • https://github.com/harfbuzz/harfbuzz/pull/3954
  • https://github.com/fribidi/fribidi/pull/193
• Fix find_program and subproject usage

The purpose of these fixes is correctness and to make it easier to build gtk on Windows as a subproject, such as, as a part of gstreamer.

CC: @fanc999 for the first commit, please test whether the change works for you. It should, and it's simpler!