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/test/fuzz/string.cpp

@@ -5,6 +5,7 @@
 #include <blockfilter.h>
 #include <clientversion.h>
 #include <common/args.h>
+#include <common/messages.h>
 #include <common/settings.h>
 #include <common/system.h>
 #include <common/url.h>
@@ -21,8 +22,6 @@
 #include <test/fuzz/FuzzedDataProvider.h>
 #include <test/fuzz/fuzz.h>
 #include <test/fuzz/util.h>
-#include <util/error.h>
-#include <util/fees.h>
 #include <util/strencodings.h>
 #include <util/string.h>
 #include <util/translation.h>
@@ -37,6 +36,11 @@
 
 enum class FeeEstimateMode;
 
+using common::AmountErrMsg;
+using common::AmountHighWarn;
+using common::FeeModeFromString;
+using common::ResolveErrMsg;
+
 FUZZ_TARGET(string)
 {
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());