This change introduces a new EditorThemeManager class
to abstract theme generatio and its subroutines.
Logic related to EditorTheme, EditorColorMap, and editor
icons has been extracted into their respective files with
includes cleaned up.
All related files have been moved to a separate folder to
better scope them in the project. This includes relevant
generated files as well.
Non-exhaustive list of case-sensitive renames:
GDExtension -> GDNative
GDNATIVE -> GDEXTENSION
gdextension -> gdnative
ExtensionExtension ->Extension (for where there was GDNativeExtension)
EXTENSION_EXTENSION ->EXTENSION (for where there was GDNATIVE_EXTENSION)
gdnlib -> gdextension
gdn_interface -> gde_interface
gdni -> gde_interface
Keeping CONTRIBUTING.md at the root so that contributors actually find it.
Also changed the custom FUNDING.yml link to point to godotengine.org/donate,
which also links to PayPal and other options.
