Remove "Rename inline" option

The new view-engine currently does not support inline-renaming
and because of more important pending issues this cannot be
implemented for the 4.8 release of KDE applications.

The plan for 4.9 is to implement inline-renaming again and
to make it "so good" (tm) that it is always turned on (-> there is
no need anymore for an option to disable it ;-)

CCBUG: 286893