session: hotfix for schema and locale check

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
oaiharvester: refextract task fix

* Checks properly if the PDF is downloaded successfully inside the
  refextract task.

Reviewed-by: Jan Aage Lavik <jan.age.lavik@cern.ch>
Signed-off-by: Georgios Papoutsakis <georgios.papoutsakis@cern.ch>
template: fix for unicode url handling

Signed-off-by: Esteban J. G. Gabancho <esteban.gabancho@gmail.com>
formatter: addition of format.mime_type column

* Adds upgrade for the `Format` table by adding `mime_type`.

Signed-off-by: Konstantinos Kostis <konstantinos.kostis@cern.ch>
records: REST API addition

* Adds REST API for records.

* Sets `clean=True` in legacy search_engine to clean the
  recjson to be returned.

Signed-off-by: Konstantinos Kostis <konstantinos.kostis@cern.ch>