PR Comment: Language Spec: Hex serialization

Many binary data objects such as cryptographic keys and hash values are traditionally displayed in hex format.

The Language Spec defines a Binary type that, when using OpenC2's verbose JSON serialization, is serialized as a base64url string.

Propose that the serialization table in Section 3.1.5 line 506 define a new subtype:

Binary.x - JSON string containing hex encoding of the binary value as defined in Section 8 of RFC 4648.

Propose that at line 484, the IP-Addr, MAC-Addr, Request-Id, and UUID types have Base Type "Binary.x"

Propose that at line 806, all hashes have Type "Binary.x"

Note that section 3.4.2.8 defines a binary artifact payload that should use base64url encoding, so both the Binary type and the Binary.x subtype are required.