Integrate ASN bucketing in Addrman and add tests

Instead of using /16 netgroups to bucket nodes in Addrman for connection
diversification, ASN, which better represents an actor in terms
of network-layer infrastructure, is used.
For testing, asmap.raw is used. It represents a minimal
asmap needed for testing purposes.

src/net.h

@@ -153,6 +153,7 @@ public:
         bool m_use_addrman_outgoing = true;
         std::vector<std::string> m_specified_outgoing;
         std::vector<std::string> m_added_nodes;
+        std::vector<bool> m_asmap;
     };
 
     void Init(const Options& connOptions) {
@@ -330,6 +331,8 @@ public:
     */
     int64_t PoissonNextSendInbound(int64_t now, int average_interval_seconds);
 
+    void SetAsmap(std::vector<bool> asmap) { addrman.m_asmap = asmap; }
+
 private:
     struct ListenSocket {
     public: