Add ttl_options setting

Adds a new setting to define the options in the TTL dropdown when
editing a record. The setting is a comma separated string with the
valid options.

app/templates/domain.html

@@ -106,6 +106,7 @@
 <script>
     // superglobals
     window.records_allow_edit = {{ editable_records|tojson }};
+    window.ttl_options = {{ ttl_options|tojson }};
     window.nEditing = null;
     window.nNew = false;