refactor: Avoid positional params for MessageList.

We used to have positional parameters for table_name
and filter, but we don't use them for message_list.all
and we're about to replace filter in some cases.

Passing everything in on opts is more consistent and
self-documenting in the calling code, plus lots of
unit tests can get away with passing in `{}` now
for situations where table_name does not matter.

All of our callers pass in muting_enabled, so we
remove the default value for it.  And then the
collapse_messages variable doesn't have to live on
`this` as it's only being passed through down to the
view.

static/js/zulip.js

@@ -2,12 +2,11 @@
 // global variables from Zulip (everything is being moved into
 // modules).  Please don't add things here.
 
-var home_msg_list = new message_list.MessageList(
-    'zhome',
-    new Filter([{operator: "in",
-                 operand: "home"}]),
-    {muting_enabled: true}
-);
+var home_msg_list = new message_list.MessageList({
+    table_name: 'zhome',
+    filter: new Filter([{operator: "in", operand: "home"}]),
+    muting_enabled: true,
+});
 var current_msg_list = home_msg_list;
 
 if (typeof module !== 'undefined') {