For every peer expose through `getpeerinfo` RPC whether or not we selected them as HB peers, and whether or not they selected us as HB peers.

Suggestion by @gmaxwell.
{RPCResult::Type::BOOL, "relaytxes", "Whether peer has asked us to relay transactions to it"},
                            {RPCResult::Type::NUM_TIME, "lastsend", "The " + UNIX_EPOCH_TIME + " of the last send"},
                            {RPCResult::Type::NUM_TIME, "lastrecv", "The " + UNIX_EPOCH_TIME + " of the last receive"},
                            {RPCResult::Type::NUM_TIME, "last_transaction", "The " + UNIX_EPOCH_TIME + " of the last valid transaction received from this peer"},
                            {RPCResult::Type::NUM_TIME, "last_block", "The " + UNIX_EPOCH_TIME + " of the last block received from this peer"},
                            {RPCResult::Type::NUM, "bytessent", "The total bytes sent"},
                            {RPCResult::Type::NUM, "bytesrecv", "The total bytes received"},
                            {RPCResult::Type::NUM_TIME, "conntime", "The " + UNIX_EPOCH_TIME + " of the connection"},
                            {RPCResult::Type::NUM, "timeoffset", "The time offset in seconds"},
                            {RPCResult::Type::NUM, "pingtime", "ping time (if available)"},
                            {RPCResult::Type::NUM, "minping", "minimum observed ping time (if any at all)"},
                            {RPCResult::Type::NUM, "pingwait", "ping wait (if non-zero)"},
                            {RPCResult::Type::NUM, "version", "The peer version, such as 70001"},
                            {RPCResult::Type::STR, "subver", "The string version"},
                            {RPCResult::Type::BOOL, "inbound", "Inbound (true) or Outbound (false)"},
                            {RPCResult::Type::BOOL, "addnode", "Whether connection was due to addnode/-connect or if it was an automatic/inbound connection\n"
                                                               "(DEPRECATED, returned only if the config option -deprecatedrpc=getpeerinfo_addnode is passed)"},
                            {RPCResult::Type::STR, "connection_type", "Type of connection: \n" + Join(CONNECTION_TYPE_DOC, ",\n") + ".\n"
                                                                      "Please note this output is unlikely to be stable in upcoming releases as we iterate to\n"
                                                                      "best capture connection behaviors."},
                            {RPCResult::Type::NUM, "startingheight", "The starting height (block) of the peer"},
                            {RPCResult::Type::NUM, "banscore", "The ban score (DEPRECATED, returned only if config option -deprecatedrpc=banscore is passed)"},
                            {RPCResult::Type::NUM, "synced_headers", "The last header we have in common with this peer"},
                            {RPCResult::Type::NUM, "synced_blocks", "The last block we have in common with this peer"},
                            {RPCResult::Type::ARR, "inflight", "",
                            {
                                {RPCResult::Type::NUM, "n", "The heights of blocks we're currently asking from this peer"},
                            }},
                            {RPCResult::Type::BOOL, "whitelisted",  true, "Whether the peer is whitelisted with default permissions\n"
                                                                                        "(DEPRECATED, returned only if config option -deprecatedrpc=whitelisted is passed)"},