Add basic lua scripting capabilities (#4341)

The scripting capabilities is locked behind a cmake flag, and is not enabled by default.

Co-authored-by: nerix <nerixdev@outlook.de>
Co-authored-by: pajlada <rasmus.karlsson@pajlada.com>

.gitmodules

@@ -35,6 +35,9 @@
 [submodule "lib/miniaudio"]
 	path = lib/miniaudio
 	url = https://github.com/mackron/miniaudio.git
+[submodule "lib/lua/src"]
+	path = lib/lua/src
+	url = https://github.com/lua/lua
 [submodule "lib/crashpad"]
 	path = lib/crashpad
 	url = https://github.com/getsentry/crashpad