Request to add client and server logic for protocol version awareness

[TorfinnOlsen]

Work was completed to add deal sealing and indexer announcement configurability behaviors here:
#1051 (comment)

in support of this FRC:
https://github.com/filecoin-project/FIPs/blob/f30244781db571d3b0420f414be28e6d84cfa1f9/FRCs/frc-0056.md

However, in order for this functionality to actually work and be usable we need the client and server to recognize the protocol version (including the new version v1.2.1).

The desirable behavior is that the protocol will default to the earliest version either the client or server supports.