Add mapper 474

[Akeraiotitasoft]

Mapper to use Extra PRG_ROM space without bank switching. Akerasoft Mapper 474 and Akerasoft Mapper 474 submapper 3 with battery.

[daniel5151]

Looks reasonable to me!

Before merging, I thought I might ask for a favor: any chance you could take a stab at updating the CI scripts to use that new version of the artifact-upload task it is complaining about?

Given that this project is in pretty deep maintenance mode at this point, I'm OK with merging without fixing CI... but if you have some cycles to spare, it would be great to actually have downloadable artifacts that include your particular patch available for folks to download.