deposit: support of multiple subjects

* Allows to select multiple subjects using the Bootstrap
  multiselect library for the frontend.

NOTE: run `grunt` to copy the external libraries.

Signed-off-by: Georgios Kokosioulis <georgios.kokosioulis@cern.ch>
Merge pull request #8 from giokokos/multiple-subjects

deposit: support of multiple subjects
deposit: translated title field

* Adds translated title field if the selected language isn't English.

Signed-off-by: Pedro Gaudêncio <pedro.gaudencio@cern.ch>
deposit: language underneath title

* Moves both the language and the translated title fields underneath the main
  title field.

Signed-off-by: Pedro Gaudêncio <pedro.gaudencio@cern.ch>
Merge pull request #6 from pedrogaudencio/deposit-translated-title

deposit: translated title field
deposit: display fixes

* Fixes the layout without touching the .container class
  from core Bootstrap and sets proper breakpoint.

* Adds new styles for the Instructions box.

* Smoothly collapsing panels.

Signed-off-by: Georgios Kokosioulis <georgios.kokosioulis@cern.ch>