detect/xform: Support transform identity data

detect/xform: Support transform identity data

Transforms that support optional strings, like from_base64 and
pcrexform, should also support identity-strings to treat transforms with
like transform options as the same.

This commit adds transform identity data handling:
- When computing a hash, include identity data from the transform
- When comparing, include the identity data from the transforms
- Omitting the "options" ptr from the transform hash/compare
- Modify xor, pcrexform and from_base64 to supply identification data for
  disambiguation in the compare/hash logic.