Implement serialization for Dijkstra era Block Body #5380
Description
This is a follow up ticket to #5046
Depending on the outcome of the CIP-??? - Non-segregated Block Body Serialization we will have different serialization implementation for the sequence of transactions in the block body. In case that this CIP is rejected then serialization will be quite a bit more complicated, therefore we are forced to wait on its resolution, before we sink resources unnecessarily into this problem.