Remove Edit menu

This menu providers a few text editing related functions, like undo/redo, copy, paste, etc.
As far as I can tell, it never worked in a useful way, though: It operates on the activeFocusItem,
but as soon as one clicks on the menu, this becomes null. It is somewhat useable through shortcuts,
but the text fields have these shortcuts natively.

src/app/CMakeLists.txt

@@ -122,7 +122,6 @@ if(NOT ANDROID AND NOT WIN32)
     qt_target_qml_sources(neochat QML_FILES
         qml/ShareAction.qml
         qml/GlobalMenu.qml
-        qml/EditMenu.qml
     )
 else()
     qt_target_qml_sources(neochat QML_FILES