Make Qmake copy res directory instead of OS scripts

Since Qt 5.6 Qmake has supported the (undocumented) file_copies
function.

Moving to an OS independent version is superior for obvious
reasons.

Use in
https://stackoverflow.com/questions/3984104/qmake-how-to-copy-a-file-to-the-output/54162789#54162789

Uses the same interface as the INSTALLS function described here
https://doc.qt.io/qt-5/qmake-advanced-usage.html#installing-files

Implemented in the file_copies.prf file found here
https://code.qt.io/cgit/qt/qtbase.git/log/mkspecs/features/file_copies.prf

build_scripts/linux/build_linux.sh

@@ -12,7 +12,7 @@ qmake --version
 qmake -spec $QMAKE_SPEC $PROJECT_DIR $QMAKE_EXTRAS
 $MAKE_COMMAND
 $CLANG_TIDY
-cp -r $PROJECT_DIR/src/res $BUILD_DIR/bin/linux/AdvancedSettings/
+
 cp $PROJECT_DIR/src/package_files/action_manifest.json $BUILD_DIR/bin/linux/AdvancedSettings/
 cp $PROJECT_DIR/src/package_files/manifest.vrmanifest $BUILD_DIR/bin/linux/AdvancedSettings/
 cp -r $PROJECT_DIR/src/package_files/default_action_manifests $BUILD_DIR/bin/linux/AdvancedSettings/

build_scripts/win/build.py

@@ -127,9 +127,6 @@ def deploy():
     copy_file(get_project_dir() + "\\third-party\\openvr\\LICENSE", get_deploy_dir() + "\\LICENSE-VALVE.txt")
     copy_file(get_project_dir() + "\\third-party\\easylogging++\\LICENSE", get_deploy_dir() + "\\LICENSE-MIT.txt")
 
-    #res
-    copy_folder(get_project_dir() + "\\src\\res", get_deploy_dir() + "\\res")
-
     #package files
     copy_folder(get_project_dir() + "\\src\\package_files", get_deploy_dir())