Completed smart block, playlist, and webstream editor form overhauls

* CC-6088: Smart Block form needs to have a form layout
* CC-6089: Editor view name fields must be made <input> fields
* CC-6103: Cannot create webstreams
* Reworked a big chunk of the smart block editor flow to send only the
  playlist contents back rather than the entire HTML fragment for the
  editor.
* Keep more of the playlist/smartblock editor view persistent across
  saves, generates, and shuffles.

airtime_mvc/public/css/playlist_builder.css

@@ -604,4 +604,8 @@ li.spl_empty {
 }
 .expand-block-separate {
     border-top: 1px solid #5B5B5B;
+}
+
+#criteria_add {
+    margin-bottom: 5px;
 }