Burn should support alternate hash algorithms

[barnson]

• Describe the scenario and benefits that the feature supports.

Burn uses SHA-1 hashes for payload verification. IBootstrapperEngine::SetUpdate takes a BOOTSTRAPPER_UPDATE_HASH_TYPE which has only two values:

BOOTSTRAPPER_UPDATE_HASH_TYPE_NONE,
BOOTSTRAPPER_UPDATE_HASH_TYPE_SHA1,

which means that if you want to use a "better" hash algorithm, you have to pass in BOOTSTRAPPER_UPDATE_HASH_TYPE_NONE and get no hash checking whatsoever.

• Describe how you're accomplishing the feature today (if possible).

Not.

• Describe what you'd like the new feature to do.

All the underlying hash checking Burn uses support whatever Windows supports. Burn shouldn't be so restrictive. Alternatively, it should switch to SHA-256 to a get "modern" algorithm.

[rseanhall]

I was expecting to do this as part of #3992 - replacing SHA1 with SHA512.

[barnson]

Yeah, that's the "at least" scenario.