Add support for NDS devkit (8MB) and 3DS (32MB) MainRAM configurations

[shinyquagsire23]

• Both JIT/interpreter are tested and working (afaict)
• 32MB is tested against BlocksDS's detection heuristics and matching my tests against 3DS vs DSi
  • Including memory mirrors vs open bus behavior, open-bus is the default expected by applications (and was the default before this PR), the memory mirroring at 0x0D000000 is untested at the moment because SCFG writes are ignored and it's a bit edge-casey behavior anyway.
• 8MB (NDS devkit) is completely untested and might not even exist for all I know, but GBATEK has at least one mention of the configuration and the current mirroring behavior should be fine. Maybe useful for prototype dumps or something.