Clean up menus in MessageList

* Final list of options while normal mailbox is shown
* New list of options while smart folder is shown
* Correct lists of context options for drafts, outbox, trash, and
    everywhere else (full list)
* Enable reply, reply all, and forward

TODO: needs a better icon for menu->folders

Resolves bug 1904421 items 4a, 4b, 5a
Resolves bug 2078092
1 file changed