deposit: removal of the unneeded code

* Removes constructor assignment at fields_group.js

Signed-off-by: Kamil Neczaj <kamil.neczaj@cern.ch>
deposit: conferences field typeahead

* NOTE: uses data mock. Should be changed to the real data source once
  recjson output is available.

Signed-off-by: Kamil Neczaj <kamil.neczaj@cern.ch>
Reviewed-by: Javier Martin Montull <javier.martin.montull@cern.ch>
deposit: trimming identifiers before import

Signed-off-by: Kamil Neczaj <kamil.neczaj@cern.ch>