rpc: add getblockchaininfo and getnetworkinfo

Adds two new info query commands that take over information from
hodge-podge `getinfo`.

Also some new information is added:
- `getblockchaininfo`
  - `chain`: (string) current chain (main, testnet3, regtest)
  - `verificationprogress: (numeric) estimated verification progress
  - `chainwork`
- `getnetworkinfo`
  - `localaddresses`: (array) local addresses, from mapLocalHost (fixes #1734)

src/net.cpp

@@ -44,18 +44,13 @@ static const int MAX_OUTBOUND_CONNECTIONS = 8;
 bool OpenNetworkConnection(const CAddress& addrConnect, CSemaphoreGrant *grantOutbound = NULL, const char *strDest = NULL, bool fOneShot = false);
 
 
-struct LocalServiceInfo {
-    int nScore;
-    int nPort;
-};
-
 //
 // Global state variables
 //
 bool fDiscover = true;
 uint64_t nLocalServices = NODE_NETWORK;
-static CCriticalSection cs_mapLocalHost;
-static map<CNetAddr, LocalServiceInfo> mapLocalHost;
+CCriticalSection cs_mapLocalHost;
+map<CNetAddr, LocalServiceInfo> mapLocalHost;
 static bool vfReachable[NET_MAX] = {};
 static bool vfLimited[NET_MAX] = {};
 static CNode* pnodeLocalHost = NULL;