Introducing a new PKM format: SK2
Split ICaughtData2 off of PK2 so it can be shared with SK2 when type-checks occur
Add conversion for PK2<->SK2
Split the split-buffer handling for GBPKM to GBPKML (what a name), so that I can reuse shared accessor logic for SK2.
All logic in PokeCrypto is separate from the rest of the PKHeX.Core
library; makes it easy to just rip this portion out and reuse in other
projects without needing the entirety of PKHeX.Core logic
optimize out the CheckEncrypted to the actual path, separate methods.
Only usages of this method were with hardcoded Format values, so no
impact