* Add block bodies to the propagation and lookups
- Read and propagate block bodies next to the headers
- Add block bodies content (via lookups) to the eth_getBlockByHash
call
- Test the above in test_portal_testnet
* Fix storage/propagation of block bodies
- Data format is an actual block: [header, txs, uncles], which
requires some adjustment to store the block body
- Added also `eth_getBlockTransactionCountByHash` json rpc call