[ObjectYAML] Add support for DXContainer HASH

DXContainer files contain a part that has an MD5 of the generated
shader. This adds support to the ObjectYAML tooling to expand the hash
part data and hash iteself in preparation for adding hashing support to
DirectX code generation.

Reviewed By: python3kgae

Differential Revision: https://reviews.llvm.org/D136632