This adds a self-serve password reset page. Users can enter their username
and receive an email with a link that will let them create a new password.
If they've never set a password, it will send them a one-time login link
(building on #776) that will then take them to their Account Settings page.
If they don't have an email associated with their account, they'll be
instructed to contact the admin, so they can manually reset the password.

Includes changes to the stylesheet and database, so run:

    make ui
    writefreely db migrate

Closes T508

This allows setting a URL, and then renders a <link> element
in the head of the blog. It requires a database migration.

Ref T744

A Bunch Tell is now Musing Studio.

This enables users to add a signature to all blog posts, and update it from a single location.

Requires database migration with: writefreely db migrate

Closes T582