[desktop] Port some QtCommon changes from QML branch (#3703)

- Linker now resolves implementation differences
- Remove unneeded ifdefs
- Better abstractions overall

Signed-off-by: crueter <crueter@eden-emu.dev>
Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/3703
Reviewed-by: Lizzie <lizzie@eden-emu.dev>
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>

.ci/license-header.sh

@@ -115,7 +115,7 @@ for file in $FILES; do
 		*.cmake|*.sh|*CMakeLists.txt)
 			begin="#"
 			;;
-		*.kt*|*.cpp|*.h)
+		*.kt*|*.cpp|*.h|*.qml)
 			begin="//"
 			;;
 		*)
@@ -193,7 +193,7 @@ if [ "$UPDATE" = "true" ]; then
 				begin="#"
 				shell=true
 				;;
-			*.kt*|*.cpp|*.h)
+			*)
 				begin="//"
 				shell="false"
 				;;