Merge remote-tracking branch 'cbrownstein/doc/14790-update-doc-new-greeter' into doc/14790-update-doc-new-greeter

refs #12035 I thought I had deleted this already, but it looks like something went wrong. Don't load the donation banner css anymore.

Tearing down the donation campaign 2017.

Author: sajolida <sajolida@pimienta.org>
Date:   Thu Oct 19 09:39:04 2017 +0000

    Remove special treatment of banner on installation assistant (#14852)

    - Developers wondered several times whether this was on purpose or
      broken, so users probably wonder as well.
    - It make it hard to tweak the top section of our site, for example to
      include a donation banner.
    - It's broken on smaller screens and the text collapses with the logo.

I did not remove the corresponding line in the CSS - which I will delete anyway.
I'm applying this manually because cherry-picking and merging create too many conflicts.

This reverts commit 6bb75d4d.