410: Take out horizontal rule

After discussing with May we concluded it was important to have an
h1 for screen readers and to avoid a hacky solution (a first heading
is required on all pages in Vector). We will revisit this later.
https://trello.com/c/XNeZdCTT

Change-Id: I0a8a8c37dd72b482dc67d3d1460ada16be9ed228
Merge "410: Take out horizontal rule"