util: move fees.h and error.h to common/messages.h

Move enum and message formatting functions to a common/messages header where
they should be more discoverable, and also out of the util library, so they
will not be a dependency of the kernel

The are no changes in behavior and no changes to the moved code.

src/node/mempool_args.cpp

@@ -8,19 +8,20 @@
 #include <kernel/mempool_options.h>
 
 #include <common/args.h>
+#include <common/messages.h>
 #include <consensus/amount.h>
 #include <kernel/chainparams.h>
 #include <logging.h>
 #include <policy/feerate.h>
 #include <policy/policy.h>
 #include <tinyformat.h>
-#include <util/error.h>
 #include <util/moneystr.h>
 #include <util/translation.h>
 
 #include <chrono>
 #include <memory>
 
+using common::AmountErrMsg;
 using kernel::MemPoolLimits;
 using kernel::MemPoolOptions;