Remove unused anchor links placed before every page

In old versions of the viewer, anchor links were used to be able to scroll a page into view. Since we for quite some time have had a `scrollIntoView` function which handles this, the anchor links are no longer necessary and I believe that they can be removed. Doing so will reduce the total number of DOM elements in the viewer.

For most documents this patch will probably not make much of a difference performance wise, but for very long (1000+ pages) documents this could help performance especially on lower powered hardware.