installation: jinja2 prerequisite
installation: jinja2 prerequisite

* Adds jinja2 prerequisite, since it is mandatory in BibAuthorID.
  When the module is made optional, this can get revisited.
  (closes #1677)

Signed-off-by: Tibor Simko <c7116e45300b163846dc01f3ed02116e3f8ef7a5@cern.ch>

tiborsimko/invenio,inveniosoftware/invenio,inveniosoftware/invenio,tiborsimko/invenio