Add support for font weight and stretch selection when using system fonts.
Add function to get system fallback font from a font name, style, text, and language code.
Implement system font support for Android.
Use system fonts as a last resort fallback.
* Map is unnecessary and inefficient in almost every case.
* Replaced by the new HashMap.
* Renamed Map to RBMap and Set to RBSet for cases that still make sense
(order matters) but use is discouraged.
There were very few cases where replacing by HashMap was undesired because
keeping the key order was intended.
I tried to keep those (as RBMap) as much as possible, but might have missed
some. Review appreciated!
-Allows displaying custom options for specific file format variants
-Added support for scene format import to retrieve custom options
This PR is necessary for #54886 to be implemented properly.
