util: add TransactionError includes and namespace declarations

Add TransactionError to node namespace and include it directly instead of
relying on indirect include through common/messages.h

This is a followup to a previous commit which moved the TransactionError enum.
These changes were done in a separate followup just to keep the previous commit
more minimal and easy to review.

src/common/messages.cpp

@@ -7,6 +7,7 @@
 
 #include <common/types.h>
 #include <policy/fees.h>
+#include <node/types.h>
 #include <tinyformat.h>
 #include <util/strencodings.h>
 #include <util/string.h>
@@ -18,6 +19,8 @@
 #include <utility>
 #include <vector>
 
+using node::TransactionError;
+
 namespace common {
 std::string StringForFeeReason(FeeReason reason)
 {