ARI: Improve wiki documentation

This patch improves the documentation of ARI on the wiki. Specifically, it
addresses the following:
* Allowed values and allowed ranges weren't documented. This was particularly
  frustrating, as Asterisk would reject query parameters with disallowed values
  - but we didn't tell anyone what the allowed values were.
* The /play/id operation on /channels and /bridges failed to document all of
  the added media resource types.
* Documentation for creating a channel into a Stasis application failed to
  note when it occurred, and that creating a channel into Stasis conflicts with
  creating a channel into the dialplan.
* Some other minor tweaks in the mustache templates, including italicizing the
  parameter type, putting the default value on its own sub-bullet, and some
  other nicities.

Review: https://reviewboard.asterisk.org/r/4351


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/13@431145 65c4cc65-6c06-0410-ace0-fbb531ad65f3

rest-api-templates/swagger_model.py

@@ -220,6 +220,9 @@ class AllowableRange(Stringify):
         self.min_value = min_value
         self.max_value = max_value
 
+    def to_wiki(self):
+        return "Allowed range: Min: {0}; Max: {1}".format(self.min_value, self.max_value)
+
 
 class AllowableList(Stringify):
     """Model of a allowableValues of type LIST
@@ -229,6 +232,9 @@ class AllowableList(Stringify):
     def __init__(self, values):
         self.values = values
 
+    def to_wiki(self):
+        return "Allowed values: {0}".format(", ".join(self.values))
+
 
 def load_allowable_values(json, context):
     """Parse a JSON allowableValues object.