* Improve error handling in block iteration
* Introduce atomic DB operations
* Fix race condition
An invariant was violated: For every block hash in head_tracker, that
block is accessible from the store.
* Store dht enrs on shutdown
* Load enrs on startup and add tests
* Remove enr_entries from behavior
* Move all dht persisting logic to `NetworkService`
* Move `PersistedDht` from eth2-libp2p to network crate
* Add test to confirm dht persistence
* Add logging
* Remove extra call to beacon_chain persist
* Expose only mutable `add_enr` method from behaviour
* Fix tests
* Fix merge errors
* Sparse hot DB and block root tree
* Fix store_tests
* Ensure loads of hot states on boundaries are fast
* Milder error for unaligned finalized blocks
* Implement freezer database for state vectors
* Improve BeaconState safe accessors
And fix a bug in the compact committees accessor.
* Banish dodgy type bounds back to gRPC
* Clean up
* Switch to exclusive end points in chunked vec
* Cleaning up and start of tests
* Randao fix, more tests
* Fix unsightly hack
* Resolve test FIXMEs
* Config file support
* More clean-ups, migrator beginnings
* Finish migrator, integrate into BeaconChain
* Fixups
* Fix store tests
* Fix BeaconChain tests
* Fix LMD GHOST tests
* Address review comments, delete 'static bounds
* Cargo format
* Address review comments
* Fix LMD ghost tests
* Update to spec v0.9.0
* Update to v0.9.1
* Bump spec tags for v0.9.1
* Formatting, fix CI failures
* Resolve accidental KeyPair merge conflict
* Document new BeaconState functions
* Fix incorrect cache drops in `advance_caches`
* Update fork choice for v0.9.1
* Clean up some FIXMEs
* Fix a few docs/logs
* Update for new builder paradigm, spec changes
* Freezer DB integration into BeaconNode
* Cleaning up
* This works, clean it up
* Cleanups
* Fix and improve store tests
* Refine store test
* Delete unused beacon_chain_builder.rs
* Fix CLI
* Store state at split slot in hot database
* Make fork choice lookup fast again
* Store freezer DB split slot in the database
* Handle potential div by 0 in chunked_vector
* Exclude committee caches from freezer DB
* Remove FIXME about long-running test
