deposit: change of hiding method of hidden fields

* Uses HiddenInput widget in forms.py, and hides
  all leftovers generic using class based jQuery
  selector in fillform.js.

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

Signed-off-by: Kamil Neczaj <kamil.neczaj@cern.ch>
deposit: proper submision for conference

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: adaptation to fieldlist separation

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

Signed-off-by: Kamil Neczaj <kamil.neczaj@cern.ch>
deposit: task manager doc improvements

Signed-off-by: Kamil Neczaj <kamil.neczaj@cern.ch>
deposit: task manager typo fix

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