luminous: doc: show edit on github links and version warnings

luminous: doc: show edit on github links and version warnings

backport of #24452 that adds edit on
github links to documentation and notification banners that display
warnings when old documentation is being viewed.

this is not a cherry-pick: it removes from the original patch the
dynamic generation of the releases schedule from a yaml database file.
backporting this portion requires modifying the patch to deal with a
different file / directory structure [in luminous] with no real added value.

Signed-off-by: Noah Watkins <nwatkins@redhat.com>