deposit: fix for a rename not applied for form.js

* Changes fieldlist -> dynamicFieldList in
  form.js to adapt to changes at
  'fieldlist plugin separation' commit.

* Fixes undefined 'empty_cssclass'.

Signed-off-by: Kamil Neczaj <kamil.neczaj@cern.ch>
deposit: fieldlist wrapped to a prototype based class

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

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