Set save redirect paths before set_environment

[sonninnos]

Description

• Fix setting savefile_directory in override file by moving redirect set before environment set
• Add final path to RETRO_ENVIRONMENT_GET_SAVE_DIRECTORY logging, and renamed to SAVE_DIRECTORY like SYSTEM_DIRECTORY
• Comment cleanups

Without this change the path changing does work with --appendconfig, but not with overrides, even though overrides are parsed right after appends in the same manner.

So is there a better way, or can this cause other problems? Sure feels like the current order is clearly wrong in any case, and this seems fine as far as I can tell. What harm could there be for the core to get the final paths as early as possible..?

libretro.h does not explicitly say one way or the other, but makes sense to me that those paths are ready to be fetched already in retro_set_environment() and not later in retro_load_game(), since the paths are environment vars after all.