Modern Menu (#183)

* Add modern menu.
Add and include LUS cvars .cmake file for macro usage in modern menu.

* Un-ignore new .cmake

* Copy new Resolution Editor stuff from 2ship (incomplete).
Fix fullscreen checkbox.
Finish changes for new UIWidgets.
Cleanup ShipUtils.

* Remove duplicate asm-differ entry from .gitmodules.

* Re-implement Freecam options.

* Cleanup freecam character follow buttons.
Partially re-implement Multiplayer window as enhancement sidebar (needs text input widget to finish).
Cleanup disables.

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Co-authored-by: MegaMech <MegaMech@users.noreply.github.com>

.gitmodules

@@ -4,9 +4,6 @@
 [submodule "tools/decomp-permuter"]
 	path = tools/decomp-permuter
 	url = https://github.com/simonlindholm/decomp-permuter
-[submodule "tools/asm-differ"]
-	path = tools/asm-differ
-	url = https://github.com/simonlindholm/asm-differ
 [submodule "doxygen-awesome-css"]
 	path = doxygen-awesome-css
 	url = https://github.com/jothepro/doxygen-awesome-css.git