mixer: dump database fixes

* Adds new command `inveniomanage database dump` to allow dumping the
  content of the database using the mixer.

* Fixes imports and trailing white spaces on json dump.

Signed-off-by: Esteban J. G. Gabancho <esteban.gabancho@gmail.com>
search: tuning of hierarchical facet

Tested-by: Tibor Simko <tibor.simko@cern.ch>
Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
search: quickfix pagination troubles with facets

* Fixes problem with ignoring pagination options while using facets.
  (closes #2306) (PR #2308)

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
Tested-by: Tibor Simko <tibor.simko@cern.ch>
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>
jsonalchemy: dumps with specified keywords

* Adds an option to dump only specified keys from dictionary.

Signed-off-by: Leonardo Rossi <leonardo.r@cern.ch>
Reviewed-by: Jiri Kuncar <jiri.kuncar@cern.ch>
search: fix filtered output format

* Addresses issue with research and export that not accept the "ot"
  filter argument.  (closes #2292)

Signed-off-by: Leonardo Rossi <leonardo.r@cern.ch>
Reviewed-by: Jiri Kuncar <jiri.kuncar@cern.ch>