Reduce number of optional dependencies

Change some optional dependencies from being optional to being mandatory or being mandatory but behind on-by-default cmake flags. Eg: instead of only compiling Wayland support if we find the appropriate libraries, we always require the libraries unless the user specifies WITH_WAYLAND=OFF.

Optional libraries are hard to discover by packagers (since they don't see an error once we add them) and create lots of possible build flavors with a different features that can confuse users.

Depends on this change to the CI: sysadmin/ci-images!138 (merged)