refactor!: repo cleanup (#2650)

- Move cmake files to dedicated cmake folder
- Move scattered python files to `scripts/` folder
- Update CMakeLists.txt to reflect changes
* feat(scripts): add README to folder

cmake/gtav-classes.cmake

@@ -0,0 +1,14 @@
+include(FetchContent)
+
+FetchContent_Declare(
+    gtav_classes
+    GIT_REPOSITORY https://github.com/Yimura/GTAV-Classes.git
+    GIT_TAG        e8d8bdd2b3152253f6e1fde48720e4caeab19f83
+    GIT_PROGRESS TRUE
+    CONFIGURE_COMMAND ""
+    BUILD_COMMAND ""
+)
+message("GTAV-Classes")
+if(NOT gtav_classes_POPULATED)
+    FetchContent_Populate(gtav_classes)
+endif()