deposit: proper submision for conference

* Adds conference_id hidden field to forms.py.

Signed-off-by: Kamil Neczaj <kamil.neczaj@cern.ch>
deposit: bug fix for conference typeahead

Signed-off-by: Kamil Neczaj <kamil.neczaj@cern.ch>
deposit: conferences ta jshint for fillform

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