* Testing Beacon API
* Fixed sentinel code (a little bit)
* Fixed sentinel tests
* Added historical state support
* Fixed state-related endpoints (i was drunk when writing them)
* Most of the PR changed files are extra and slightly more complicated
unit tests.
* Fixed Eth1DataVotes not inheriting genesis
* Fixed Attestations simulation using wrong slot when reconstructing
partecipation
* Fixed Copy() operation on BeaconState on Eth1DataVotes
* Used correct ListSSZ type for Eth1DataVotes and HistoricalSummaries
* Fixed wrong []uint64 deltas on empty slots
What does this PR do:
* Optional Backfilling and Caplin Archive Node
* Create antiquary for historical states
* Fixed gaps of chain gap related to the Head of the chain and anchor of
the chain.
* Added basic reader object to Read the Historical state
