Search box in Wiki page should be hidden

[Kobkaew]

The search box is inconsistent with the wiki page, it should be hidden.

[uschindler]

The search box in header should also be hidden on the search page itsself, because we see it 2 times (once in header of page, once in the portal widget).

This was also done on the old GFBio page:

• Homepage with search field in header: http://www-old.gfbio.org/
• Portal without search field in header: http://www-old.gfbio.org/data-portal.html