migrated ed25519 primitives from sei-v3

[pompon0]

Copy-pasted ed25519 primitives from sei-v3 (they underlying ed25519 library is the same) and adjusted the codebase accordingly. Since we are migrating to autobahn, the changes below prefer the sei-v3 codebase conventions (lmk if you have concerns).
In particular:

• signatures are wrapped in a type now: ed25519.Signature
• PrivateKey renamed to SecretKey (and SecretKey.PubKey() to SecretKey.Public())
• added best-effort zeroize for SecretKey, copy-prevention and printing-prevention
• Vote and CommitSig now include Option[Signature], because they occur both in signed and unsigned states for some reason.
• all hashes, signatures, proto, json encodings stay backward compatible
• added change-detector test for json encodings of crypto types
• removed typeRegistry from sei-tendermin/libs/json, because it is effectively unused (only PublicKey was registered AND it was not effective, because everywhere the PublicKey was encoded, it was actually using a custom json marshaler).
• removed sei-cosmos/server/in_plage.go command, because it seems to be stale (lmk if it is actually needed)