Deprecate graphics/bugle again

It fails to build with GCC >= 8:

cc1: error: unrecognized command line option '-fdump-translation-unit'

and is no longer actively developed.

This is deprecation attempt #2 after GCC 7 has gone EOL. Nobody
has taken over maintainership since last time and -fdump-translation-unit
is not coming back. devel/apitrace is a potential replacement.