Add ability to deprecate movie formats only for specific platforms

[CasualPokePlayer]

This has use already for VBA SGB movies (which are already banned, although it still needs manual rejection) and would be generally useful given multi-platform emulators (e.g. BizHawk). This probably is best implemented by every movie format having every platform needing to either be set as "allowed" or "not allowed" instead of the current all or nothing.