multimedia/winff: revert 947a56b365f3 and take again the maintainership

• if GTK2 ports should be deprecated and then removed, it should not be done on everey concerned port, but at the framework level (i.e. Mk/Uses/lazarus.mk for FPC ports);

• in addition, only the GTK2 flavor is impacted, not the Qt ones.

Furthermore, even if I don’t use this port very often, take again its
maintainership to avoid spurious modifications.