git: add node_modules/ to .gitignore

Signed-off-by: Georgios Kokosioulis <georgios.kokosioulis@cern.ch>
deposit: creation of import buttons widget

* Adds a button to skip the import.

* Renames ArXiv to arXiv.

* Moves inline CSS styles to `deposit-inspire.css`.

Signed-off-by: Georgios Kokosioulis <georgios.kokosioulis@cern.ch>
deposit: extension of base templates of invenio

* Extends the `run_action_bar.html` and `run_group_start.html` with
  hide class to trigger the visibility of the rest of the form and
  the action bar depending on the state of the first panel of the
  form.

Signed-off-by: Georgios Kokosioulis <georgios.kokosioulis@cern.ch>
deposit: initial modal preview of the imported data

* Adds the Readmore libary to the bundles to support the more/less
  readability on abstract and authors fields.

* Adds the new `preview.html` template to render the modal window.

* Extends the LiteratureSubmissionForm and supports smooth scrolling
  to the rest of the form.

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