* Fix eth/common & web3 related deprecation warnings for fluffy
This commit uses the new types in the new eth/common/ structure
to remove deprecation warnings.
It is however more than just a mass replace as also all places
where eth/common or eth/common/eth_types or eth/common/eth_types_rlp
got imported have been revised and adjusted to a better per submodule
based import.
There are still a bunch of toMDigest deprecation warnings but that
convertor is not needed for fluffy code anymore so in theory it
should not be used (bug?). It seems to still get imported via export
leaks ffrom imported nimbus code I think.
* Address review comments
* Remove two more unused eth/common imports
- Add new content + content key functionality for header by number
- Remove EpochRecords from the network
- Add pruning call for the EpochRecords + required deprecated
functionality
- Adjust getBlock and getBlockHashByNumber to make use of the
new functionality instead
- Delete content_verifier as it was only verifying the now
deprecated EpochRecord
- EpochAccumulator got renamed to EpochRecord
- MasterAccumulator is not HistoricalHashesAccumulator
- The List size for the accumulator got a different maximum which
also result in a different encoding and HTR
Kim De Mey