Convert chain and blockfileinfo to new serialization

Summary:
For the differences between this diff and the original commit, see:

• D1450: Introduce a BlockStatus class to encapsulate CBlockIndex's validation status
• D1654: Moved CBlockFileInfo class from chain.h into its own header
• D8319: Add routine to upgrade the block tree db to index block size

This concludes backport of Core PR17896 [3/3]
Depends on D8627

Test Plan: ninja all check all

Reviewers: #bitcoin_abc, majcosta

Reviewed By: #bitcoin_abc, majcosta

Differential Revision: https://reviews.bitcoinabc.org/D8629