Add gryffus to AUTHORS, combine Fedora and openSUSE

Will show up in our in-game credits too once i resurrect the conversion
script (hopefully later today).
Combination due to living in the same OBS repositories.
(cherry picked from commit 91d6dd2a907a2827bfdae62cc51fb460132a680f)
Regenerate credits

This output was produced by running development/generate_credits.py.
(cherry picked from commit 79ed2fd62d8dffd26783b4524ace8fa396a2ae8c)