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.
#if defined(HAVE_CONFIG_H)
#include <config/bitcoin-config.h>
#endif
#include <net.h>
#include <banman.h>
#include <clientversion.h>
#include <consensus/consensus.h>
#include <crypto/sha256.h>
#include <net_permissions.h>
#include <netbase.h>
#include <node/ui_interface.h>
#include <protocol.h>
#include <random.h>
#include <scheduler.h>
#include <util/strencodings.h>
#include <util/translation.h>
#ifdef WIN32
#include <string.h>
#else
#include <fcntl.h>
#endif
#ifdef USE_POLL
#include <poll.h>
#endif
#ifdef USE_UPNP
#include <miniupnpc/miniupnpc.h>
#include <miniupnpc/upnpcommands.h>
#include <miniupnpc/upnperrors.h>
static_assert(MINIUPNPC_API_VERSION >= 10, "miniUPnPc API version >= 10 assumed");