enhancement: texture preload on startup

[Arufonsu]

(originally tested within our myra repo)

• Based on code and discussions along with MAO's project @AlexVild (thanks!).
• Massive enhancement on texture render, just load in all textures at startup and never dispose them, this way we don't need to reload them all at run time anymore.

Draft for now:

• More code needs to be written to handle live background loading
• This will obliterate any old machine that doesn't have enough memory for all textures in a game (ie: games that use way too many and heavy resources)

Resolves #450