This commits works towards #7289. It includes files that it depends on, or forward declares types when possible. It may seem like this only increases compilation time, but before this commit they depended on the other includes of the source files that use them.
* Update includes in PlatformEnvironment.cpp
* Update includes in ParkImporter.h
* Update includes of OpenRCT2.h
* Update includes in Intro.h
* Remove unused include from Input.cpp
* Update includes of Imaging.h
* Update includes in Game.h
* Update includes in Editor.h
* Update includes of Context.cpp
* Update includes in Cheats.cpp, CmdlineSprite.cpp
* Update includes of some source files
* Update includes in some cpp files
* Update includes in some cpp files
* Update includes in TextureCache.h
* Fix tests
* Update includes in Font.cpp
* Update includes in LightFX files
* Update some includes
* Fix GCC builds
* Update some includes
* Update some includes
* Update includes in FontsFamilies.*
* Update includes of Console.h
* Improve includes in Window.h
* Improve headers in Viewport.h/Window.h
* Fix MSVC build
* Fix network-less builds
* Reduce inclusion of Map.h