Cleanup: reorganize doxygen modules

- Nest compositor pages under the compositor module
- Nest GUI, DNA/RNA & externformats modules under Blender.
- Remove modules from intern which no longer exist.
- Add intern modules (atomic, eigen, glew-mx, libc_compat, locale,
  numaapi, rigidbody, sky, utfconv).
- Use 'intern_' prefix for intern modules since some of the modules
  use generic terms such as locale & atomic.

intern/numaapi/source/build_config.h

@@ -20,6 +20,10 @@
 //
 // Author: Sergey Sharybin <sergey.vfx@gmail.com>
 
+/** \file
+ * \ingroup intern_numaapi
+ */
+
 #ifndef __BUILD_CONFIG_H__
 #define __BUILD_CONFIG_H__
 

intern/numaapi/source/numaapi.c

@@ -20,6 +20,10 @@
 //
 // Author: Sergey Sharybin <sergey.vfx@gmail.com>
 
+/** \file
+ * \ingroup intern_numaapi
+ */
+
 #include "numaapi.h"
 
 #include <assert.h>

intern/numaapi/source/numaapi_linux.c

@@ -20,6 +20,10 @@
 //
 // Author: Sergey Sharybin <sergey.vfx@gmail.com>
 
+/** \file
+ * \ingroup intern_numaapi
+ */
+
 #include "build_config.h"
 
 #if OS_LINUX

intern/numaapi/source/numaapi_stub.c

@@ -20,6 +20,10 @@
 //
 // Author: Sergey Sharybin <sergey.vfx@gmail.com>
 
+/** \file
+ * \ingroup intern_numaapi
+ */
+
 #include "numaapi.h"
 
 #include "build_config.h"

intern/numaapi/source/numaapi_win32.c

@@ -20,6 +20,10 @@
 //
 // Author: Sergey Sharybin <sergey.vfx@gmail.com>
 
+/** \file
+ * \ingroup intern_numaapi
+ */
+
 #include "build_config.h"
 
 #if OS_WIN