Add native files I missed
Move Common project
Update project configurations, removed the libretro specific configs from the mixed project. Now all the configurations here are targetting libretro.
ToDo:

- Core project
- libkirk project
- zlib project
- libretro project
Add zlib and libkirk projects, removed unused configurations from other projects, only CORE project is missing now
Remove unused configurations
Finished adding project files, now we no longer need the project files from folders outside libretro.
We need to update our projects accordingly when there are changes to their project files.