* include new getter for block
* create block filters from indices
* give every block index a unique bucket
* construct block indices by bucket mmap
* almost done save for the block filters
* include block filters, need a few more small touches for fetching the proper indices by bucket
* full functionality to filter by parent root
* tests pass when using the same logic as attestations
* todo
* proper todo formatting
* first minimum slot range filter
* slot range filters pass
* more filter criteria passing
* tests passing
* add todos
* all block tests pass and work
* rem fmt
* range retrieval test
* fixed test conditions
* instantiate the other buckets
* simplify bucket lookups
* deprecate non map code
* revamp to remove old index prefixes
* create indices from data
* create indices from data
* fetch block roots by slot range
* better abstractions
* simpler abstractions
* roots rename
* comment
* preston feedback
* allow blocks without parent root
