WebDeposit: field widgets addition
WebDeposit: field widgets addition

* Introduces WTForm field widgets like JQuery calendar widget or Plupload
  field widget (html5 version).

* Removes the "scary" code from form configuration files.

* Adds Plupload as a WTForm field widget for file fields.

* Adds new config variable CFG_WEBDEPOSIT_UPLOAD_FOLDER.

Reviewed-by: Jiri Kuncar <2bdffcb416fed3002465740d19a053a39918cbe5@cern.ch>

tiborsimko/invenio-base,tiborsimko/invenio-base,inveniosoftware/invenio-base,inveniosoftware/invenio-base