BUG: 399375
This patch changes the default window actions modifier key to Meta instead of Alt, because Alt causes problems in a lot of very popular and professional software such as Blender, GIMP, Inkscape, Krita, Gravit, Shotcut or even Krita! It prevents you from using some functions in those programs. We already use Meta for a lot of things such as window tiling, so we should use it for the window actions modifier too. In general, Meta should be used in global/shell shortcuts. GNOME changed it in the past too because of those reasons. If this default will get changed we should also announce it in the next Plasma release notes to make people aware about this change.