installation: update wtforms-alchemy to 0.12.6

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

* Adds auto-generated rst from webdoc admin pages.

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
tags: REST API and testing

* Refactored the errors class so that
  the style is more pythonic.

* Fixed the algorithm that attaches tags to records
  so that if a tag is already attached to a record
  it does not re-attach the tag.

* The output of the attach-tags-to-record algorithm is
  a list of tags as json.

* Improved the algorithm that deletes tags so that
  if a tag is attached to records , firstly it deletes
  the associactions between the tag and the record and
  then safely deletes the tag.

* Refactored the tests so that they use OrderedDict so
  that is easier to assert results.

Signed-off-by: Konstantinos Kostis <konstantinos.kostis@cern.ch>
restful: fix for testing accesstoken

* Renames class RestValidator to RESTValidator.

Signed-off-by: Konstantinos Kostis <konstantinos.kostis@cern.ch>
requirements: cerberus package upgrade

* In order to support some new features of cerberus
  and output errors in the format
  {code:c, message:m,field:f} cerberus package must
  be upgraded to latest version(v 0.7) or the previous
  one(v 0.6).

Signed-off-by: Konstantinos Kostis <konstantinos.kostis@cern.ch>