Awkward navigating when lists have many entries in a month

It's really awkward navigating through busy mailboxes.
The Show Next/Previous buttons are OK for moving through small numbers of mails, but are really tedious when there are more than say 50-60 mails in a chunk.

There should be some way to quickly skip to the first and last pages, and perhaps to a particular date.

Start by locating the mailbox list navigation and pagination entry points in the JavaScript application. Define how users should reach the first and last pages or a particular date, then verify the behavior on mailboxes containing more than 50–60 messages.

Written by the indexing model from the issue text.