devel/gps: Remover requirement on gnatinspect, plus

Currently gnatinspect is useless because GNAT FSF cannot generate the
cross-reference definitions. It needs to be implmented at the compiler
level (and one day I may do it).

In the meantime, alter gps to skip as many cross-reference checks as
we can and remove gnatcoll from RUN_DEPENDS list.

While here:

1. generate all the pyc files (a bunch were missed)
2. fix pkg-plist
3. Fix locale support (use ISO8859-* instead of ISO-8859-*)

These changes were done in an attempt to solve PR/202317, but that
FreeBSD-only problem still exists (error highlight works perfectly on
DragonFly). Cause still unknown.