We don't need to handle user clicking on Zulip logo since
changing the hash via the `a` tag takes care of it automatically.
Also, cleanup the narrow.restore_home_state function since
it is no longer being used.
Go to Recent Topics on "#", no hash and "#recent_topics".
Go to Recent Topics as the last destination for escape key.
Map `a` key to All messages and change its hash to
`#all_messages`.
Anders Kaseorg
Aman Agrawal