refactor: Remove addrdb.h dependency from node.h

src/net_types.h

@@ -0,0 +1,15 @@
+// Copyright (c) 2019 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_NET_TYPES_H
+#define BITCOIN_NET_TYPES_H
+
+#include <map>
+
+class CBanEntry;
+class CSubNet;
+
+using banmap_t = std::map<CSubNet, CBanEntry>;
+
+#endif // BITCOIN_NET_TYPES_H