WebStyle: legacy request form multivalue fix

* Addresses general problem with reading multiple POST arguments of same
  name as list.

Reported-by: Raquel Jimenez Encinar <raquel.jimenez.encinar@cern.ch>
Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
WebStyle: CFG_WEBSITE_TEMPLATE_SKIN support

* Supports for including cascade style sheet called
  `CFG_WEBSITE_TEMPLATE_SKIN` in `page.html`.

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
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)

* Merge note: cherry-picked from 117a9d6f5d4ea2df2eb66bd8537db0034b4c5bca
  and adapted to maint-1.0 branch.

Reported-by: Nedko Nedkov <nedko.stefanov.nedkov@cern.ch>
Signed-off-by: Samuele Kaplun <samuele.kaplun@cern.ch>
Reviewed-by: Tibor Simko <tibor.simko@cern.ch>
Merge branch 'maint-1.0' into maint-1.1

* maint-1.0:
  installation: support for Apache-2.4

Conflicts:
	modules/miscutil/lib/inveniocfg.py

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
Merge branch 'maint-1.1'

* maint-1.1:
  installation: support for Apache-2.4
Merge branch 'master' into next

* master:
  installation: support for Apache-2.4