search: quick fix for queries with leading space

* Strips leading/trailing white space from `p` argument to `/search`.
  This quick-fixes queries like `/search?p=+ellis` that were otherwise
  leading to "Showing records 1 to 0 out of 0 results" situations.

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
base: admin drop-down menu fix

* Removes the drop-down menu from the "Admin" tab in page header.
  (addresses #2246)

Signed-off-by: Eirini Psallida <eirini.psallida@cern.ch>
search: fix query string in add-to-search

* Adds double quotes around author filed value. (closes #2251)

* Splits terms by whitespace or quotes and join them
  with proper operator. (addresses #2252)

Signed-off-by: Adrian Pawel Baran <adrian.pawel.baran@cern.ch>