FRLG RNG fixes and tweaks

[theastrogoth]

This makes several small changes to the FRLG Starter RNG program and related code:

• separates out reusable functions that can be used for other auto-RNG programs
• adds fields to the RNG Calibration display that allow for "warm starts" (i.e. starting from a known seed/advance calibration to speed up calibration by a few resets)
• some fixes to RNG calibrations
  • a way to catch and recover from rare stats OCR problems
  • fixed tracking of cumulative EVs
• adds notifactions for non-fatal errors in the Starter RNG program
• some prep for a Gift RNG program

Retested on Switch 2 -- still working, with my setup at least