installation: support for Apache-2.4
installation: support for Apache-2.4

* Enhances `--create-apache-conf` to detect if Apache-2.4 or later is
  used and produces compatible configuration WRT directory restrictions.
  (addresses #1552)

Reported-by: Nedko Nedkov <1c6e98a70536ff00f7363188eeb22bb339aa03fb@cern.ch>
Signed-Off-By: Samuele Kaplun <2e218f779e12714c314fad8ebf6b3041daa21337@cern.ch>
Reviewed-by: Tibor Simko <c7116e45300b163846dc01f3ed02116e3f8ef7a5@cern.ch>

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