Clarifying Licensing

Kdenlive's license is actually LicenseRef-KDE-Accepted-GPL. This is the opportunity to follow the REUSE spec, as recommended by the KDE project.

Update references to license (see !243 (merged) )
Update license texts (see !243 (merged) )
Fix build after COPYING removal (see !243 (merged) )
Update headers (see !245 (merged) )
Update About dialog (see frameworks/kcoreaddons!91 (merged) and frameworks/kxmlgui!73 (merged))

Edited Nov 13, 2021 by Julius Künzel