It caches SW rendered bitmaps in textures.
The cache is also updated to support data and source separately.
E.g. source is a path to an image, and if that image changes all
related cache entries needs to found and invalidated.
Limitations of SDL rederer:
- not all draw task types are supported
- image transformation is not supported
- some textures (e.g. button matrix texts) are not detected as cached
- images are not cached
- images are supported only from path
Kconfig and MicroPython config is not updated yet.
* start to refactor lv_conf.h
* further mem refactoring
* create lv_mem_builtin.c/h
* update lv_conf_internal.h
* add lv_strlen and lv_strncpy
* rename LV_DRAW_COMPLEX to LV_USE_DRAW_MASK
* update lv_conf_template
* minor fix
