BibKnowledge: internationalisation fix

Signed-off-by: Javier Martin Montull <javier.martin.montull@cern.ch>
classifier: registry definition fix

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
installation: fix six version

* Addresses issue with creating forms based on WTForms-Alchemy.
  (addresses #1800)

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
docs: nit-picky documentation

* Adds nit-picky sphinx-build in travis build.

* Adds placeholder documents for the missing pages.

* Comments out all the badly documented modules.

* NOTE you can test that the documentation is fine by building
  it using: $ sphinx-build -nWE docs docs/_build/html

Signed-off-by: Yoan Blanc <yoan.blanc@cern.ch>
docs: admin guides port from webdoc

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