security/py-slip10: Add new port

slip10 is a reference implementation of the SLIP-0010 specification,
which generalizes BIP-0032 hierarchical deterministic key derivation for
multiple curves, including secp256k1, NIST P-256, ed25519, and
curve25519.

It supports deriving extended private and public keys along standard
paths and can operate from either seed material or serialized extended
keys.