Remove confusing CAddrDB

The class only stores the file path, reading it from a global. Globals
are confusing and make testing harder.

The method reading from a stream does not even use any class members, so
putting it in a class is also confusing.

src/addrdb.cpp

@@ -170,22 +170,19 @@ bool CBanDB::Read(banmap_t& banSet)
     return true;
 }
 
-CAddrDB::CAddrDB()
-{
-    pathAddr = gArgs.GetDataDirNet() / "peers.dat";
-}
-
-bool CAddrDB::Write(const CAddrMan& addr)
+bool DumpPeerAddresses(const ArgsManager& args, const CAddrMan& addr)
 {
+    const auto pathAddr = args.GetDataDirNet() / "peers.dat";
     return SerializeFileDB("peers", pathAddr, addr, CLIENT_VERSION);
 }
 
-bool CAddrDB::Read(CAddrMan& addr)
+bool ReadPeerAddresses(const ArgsManager& args, CAddrMan& addr)
 {
+    const auto pathAddr = args.GetDataDirNet() / "peers.dat";
     return DeserializeFileDB(pathAddr, addr, CLIENT_VERSION);
 }
 
-bool CAddrDB::Read(CAddrMan& addr, CDataStream& ssPeers)
+bool ReadFromStream(CAddrMan& addr, CDataStream& ssPeers)
 {
     return DeserializeDB(ssPeers, addr, false);
 }