[FEAT] Move hardcoded configuration outside of network library

[AndrewWestberg]

Some configuration when connecting to a network is currently hardcoded. An example of this is the last byron block where we start syncing from. Today, to add a new network to be supported by rust-cardano-ouroboros-network, we have to manually add it to the codebase.

Instead, allow this list of intersect blocks to be passed into the library as initial configuration or set it up as a callback to retrieve this list.