[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/instream.h

@@ -8,6 +8,13 @@
  *              Copyright 2017-2018 Hermes Belusca-Maito
  */
 
+/**
+ * @file    instream.h
+ * @ingroup ConUtils
+ *
+ * @brief   Console I/O utility API -- Input
+ **/
+
 #ifndef __INSTREAM_H__
 #define __INSTREAM_H__
 
@@ -32,10 +39,6 @@ extern "C" {
 // Shadow type, implementation-specific
 typedef struct _CON_STREAM CON_STREAM, *PCON_STREAM;
 
-/*
- * Console I/O utility API -- Input
- */
-
 
 #ifdef __cplusplus
 }