* Revert previous change in PortalStream. Allow zero as a valid connectionId if randomly generated.
* Rename portal_*Gossip JSON-RPC endpoints to portal_*PutContent to be in line with updated portal spec.
* Create separate portal rpc handlers for each sub-network.
* Remove random gossip from history and state networks.
* Move shared portal rpc endpoints into common handler.
* Use enum instead of network string.