Refactor message generator

* Job object can now control the output and generate K:V output for
  notification types that can support it
* Notifications store the body as json/dict now to encode more
  information
* Notification Type can further compose the message based on what is
  sensible for the notification type
* This will also allow customizing the message template in the future
* All notification types use sane defaults for the level of detail now

awx/main/notifications/webhook_backend.py

@@ -4,12 +4,12 @@
 import logging
 
 import requests
-
-from django.core.mail.backends.base import BaseEmailBackend
+import json
+from awx.main.notifications.base import TowerBaseEmailBackend
 
 logger = logging.getLogger('awx.main.notifications.webhook_backend')
 
-class WebhookBackend(BaseEmailBackend):
+class WebhookBackend(TowerBaseEmailBackend):
 
     init_parameters = {"url": {"label": "Target URL", "type": "string"},
                        "headers": {"label": "HTTP Headers", "type": "object"}}
@@ -20,11 +20,16 @@ class WebhookBackend(BaseEmailBackend):
         self.headers = headers
         super(WebhookBackend, self).__init__(fail_silently=fail_silently)
 
+    def format_body(self, body):
+        logger.error("Generating body from {}".format(str(body)))
+        return body
+
     def send_messages(self, messages):
         sent_messages = 0
         for m in messages:
+            logger.error("BODY: " + str(m.body))
             r = requests.post("{}".format(m.recipients()[0]),
-                              data=m.body,
+                              data=json.dumps(m.body),
                               headers=self.headers)
             if r.status_code >= 400:
                 logger.error("Error sending notification webhook: {}".format(r.text))