Changed ca_errmsg callback to a more generic variant

Includes all error, log and debug messages
See [Customized NETCONF error message](https://github.com/clicon/clixon/issues/454)

lib/src/clixon_string.c

@@ -52,6 +52,8 @@
 #include "clixon_hash.h"
 #include "clixon_handle.h"
 #include "clixon_string.h"
+#include "clixon_yang.h"
+#include "clixon_xml.h"
 #include "clixon_err.h"
 
 /*! Split string into a vector based on character delimiters. Using malloc