[1.0.1] Add missing data to block_header_state and change verify_qc_claim to use block_header_state data rather than only looking up a block_state in the fork database

[greg7mdp]

Resolves #694.

Implements updates described in issue #694:

• store policy generation numbers in every block_ref of the finality_core
• maintains latest_qc_claim_block_active_finalizer_policy in block_header_state
• new snapshot format (v8) which adds these new members. v7 format of spring 1.0 is unsupported.
• new fork_database format (version 3). version 2 not loaded anymore, but version 1 (legacy fork_db only) OK.
• update the serialization of the finalizer safety file, so it doesn't change even though the block_ref struct has two new members.
• add version to chain_head.dat file and do not load existing version.
• updated qc validation which does not require the fork database anymore, all needed info is in the parent block_header_state
• add new test (verify_spring_1_0_block_compatibitity) validating that this PR's changes do not affect the block ids generated.
• update tests impacted by the change, including adding to repo new snapshot v8 reference files.

[ericpassmore]

Note:start
category: Other
component: Internal
summary: Enhance Block Header State and only use provided block data to verify QC claims.
Note:end

[arhag]

By the way, your PR description says "all needed info is in the root block_header_state" but it should say "all needed info is in the parent block_header_state".