base: less files refactoring

* Moves base .less files to base/ folder. This aligns with
  Invenio's bundles.py dependencies parameter.

Signed-off-by: Javier Martin Montull <javier.martin.montull@cern.ch>
deposit: requirejs adaptation

* Adapts all deposit JS code to requirejs.

* FIXME: in order to load modules, the extension .js is needed
  which should not be the case. The cause should be investigated.

Signed-off-by: Javier Martin Montull <javier.martin.montull@cern.ch>
deposit: jsbeautifier changes

Signed-off-by: Javier Martin Montull <javier.martin.montull@cern.ch>
deposit: arXiv/DOI/ISBN fields import validation

* Allow arXiv/DOI/ISBN import only if it's well formatted.

* Adds tooltip to import button.

Signed-off-by: Pedro Gaudêncio <pedro.gaudencio@cern.ch>
deposit: fix to message box multiple append

Signed-off-by: Pedro Gaudêncio <pedro.gaudencio@cern.ch>