deposit: not show hidden fields on import preview

* Removes redundant `hidden` class.

* Improves the selector of the hidden fields.

* Fixes #151.

Signed-off-by: Georgios Kokosioulis <georgios.kokosioulis@cern.ch>
deposit: removal of group fields

* Removes the duplicated `license_url`.

* Removes the hidden `note`.

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