i18n-de: rename noun "entfernt" to "Gegenseite"

The German translation for "remote" as "entfernt" can be misleading
in situations where remote is used as a noun. "entfernt" is not a
noun and can also mean "removed". To clarify this we rename "remote"
to "Gegenseite" when used as a noun.

--HG--
branch : stable
localrepo: drop unused variable
doc: bump copyright year
merge with stable