Replace addrman.h include with forward decl in net.h

Also, add missing addrman.h includes

src/test/fuzz/connman.cpp

@@ -2,6 +2,7 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+#include <addrman.h>
 #include <chainparams.h>
 #include <chainparamsbase.h>
 #include <net.h>