WebStyle: display restriction note for bibdocs
WebStyle: display restriction note for bibdocs

* Explicitely display a restriction note above restricted bibdocs
  in "Files" tab.

* Added regression tests to ensure that restriction flag is displayed
  on "Files" tab for restricted bibdocs, as well as on other tabs when
  the entire record is restricted.

tiborsimko/invenio-records,tiborsimko/invenio-search,inveniosoftware/invenio-records,inveniosoftware/invenio-search,tiborsimko/invenio-records,tiborsimko/invenio-search,inveniosoftware/invenio-search,inveniosoftware/invenio-records