[CONUTILS] Diverse improvements: start doxygenating and add some resource messsage helper functions.

- Start to doxygenate the library, focusing in great details on the
  functions of the "outstream" module.
- Add a K32LoadStringEx function that expands (K32)LoadString by
  allowing a LanguageId parameter to be able to load strings from other
  languages than the current one.
- Add "ConResMsg*" helper functions to be able to (format and) print
  message strings with inserts that come *NOT* from a message table (as
  usual) *BUT* from resource string tables.
  Will be helpful for CORE-14265 in particular.

[CMD] Fix the call to ConMsgPrintfV().

sdk/lib/conutils/stream.c

@@ -8,6 +8,13 @@
  *              Copyright 2017-2018 Hermes Belusca-Maito
  */
 
+/**
+ * @file    stream.c
+ * @ingroup ConUtils
+ *
+ * @brief   Console I/O streams
+ **/
+
 /*
  * Enable this define if you want to only use CRT functions to output
  * UNICODE stream to the console, as in the way explained by
@@ -37,10 +44,6 @@
 #include "stream_private.h"
 
 
-/*
- * Console I/O streams
- */
-
 /*
  * Standard console streams, initialized by
  * calls to ConStreamInit/ConInitStdStreams.