Moved core logic from app_stasis to res_stasis

After some discussion on asterisk-dev, it was decided that the bulk of
the logic in app_stasis actually belongs in a resource module instead
of the application module.

This patch does that, leaves the app specific stuff in app_stasis, and
fixes up everything else to be consistent with that change.

 * Renamed test_app_stasis to test_res_stasis
 * Renamed app_stasis.h to stasis_app.h
   * This is still stasis application support, even though it's no
     longer in an app_ module. The name should never have been tied to
     the type of module, anyways.
 * Now that json isn't a resource module anymore, moved the
   ast_channel_snapshot_to_json function to main/stasis_channels.c,
   where it makes more sense.

Review: https://reviewboard.asterisk.org/r/2430/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@385742 65c4cc65-6c06-0410-ace0-fbb531ad65f3

res/res_stasis_websocket.c

@@ -24,7 +24,7 @@
  */
 
 /*** MODULEINFO
-	<depend type="module">app_stasis</depend>
+	<depend type="module">res_stasis</depend>
 	<depend type="module">res_http_websocket</depend>
 	<support_level>core</support_level>
  ***/
@@ -33,11 +33,11 @@
 
 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 
-#include "asterisk/app_stasis.h"
 #include "asterisk/astobj2.h"
 #include "asterisk/http_websocket.h"
 #include "asterisk/json.h"
 #include "asterisk/module.h"
+#include "asterisk/stasis_app.h"
 #include "asterisk/strings.h"
 #include "asterisk/utils.h"
 
@@ -322,6 +322,6 @@ static int unload_module(void)
 AST_MODULE_INFO(ASTERISK_GPL_KEY, 0, "Stasis HTTP bindings",
                 .load = load_module,
                 .unload = unload_module,
-                .nonoptreq = "app_stasis,res_http_websocket",
+                .nonoptreq = "res_stasis,res_http_websocket",
                 .load_pri = AST_MODPRI_APP_DEPEND,
         );