feat: add stateless crate to expose stateless validation

[kevaundray]

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This PR adds a method to stateless verify a block, given the ExecutionWitness and ancestor headers.

[kevaundray]

Note to keep an eye on the time for the ef-tests, since they now also create ExecutionWitnesses

[kevaundray]

Merged a few PRs in so diff looks larger than it should be:

• #15758 (For the exlcusion proof)
• #15786 (For no-std compatibility)
• #15821 (For no-std compatibility)
• #15803 (since we need the code there to make invalid blocks pass when executing each block individually)

[mattsse]

@kevaundray let me rebase this real quick

[mattsse]

okay nvm, I think you managed already ty:)