deposit: change of element for displaying import messages

Signed-off-by: Kamil Neczaj <kamil.neczaj@cern.ch>
deposit: workaround for button() function conflict

* Resigns from button() from bootstrap.js, as it is problematic to
  preserve the proper loading order with all-the-time changing
  invenio.

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