P2P: Add new peer-log-format options

[heifner]

• Add new options _peer and _nver to peer-log-format.
  • _peer - The configured p2p-peer-address or reported address if incoming.
  • _nver - The P2P network protocol version of the connection. e.g. 9 is proto_savanna, 10 is proto_block_nack.
  • Changed the default to use _peer instead of _name as _peer is easier to correlate with configured p2p-peer-address.
• Add log when not sending a block because connection is busy sending already.

[greg7mdp]

I think it might be cleaner to have another enqueue_buffer version, which doesn't take a std::optional<block_num_type> block_num, but which calls the other one with std::nullopt. But fine as it is if you prefer.

[ericpassmore]

Note:start
category: Other
component: P2P
summary: Add new options _peer and _nver to peer-log-format.
Note:end