Refactor out translation.h

This is a prerequisite for introducing bilingual error messages.
Note: #includes are arranged by clang-format-diff.py script.

src/timedata.cpp

@@ -12,6 +12,7 @@
 #include <sync.h>
 #include <ui_interface.h>
 #include <util/system.h>
+#include <util/translation.h>
 #include <warnings.h>