WebStyle: option to disable loading of blueprints
WebStyle: option to disable loading of blueprints

* Add new config option CFG_FLASK_DISABLED_BLUEPRINTS which takes a
  comma-separated list of blueprint modules which should be disabled
  (i.e. not registered with the Flask application).

Reviewed-by: Jiri Kuncar <2bdffcb416fed3002465740d19a053a39918cbe5@cern.ch>

inveniosoftware/invenio-base,tiborsimko/invenio-base,tiborsimko/invenio-base,inveniosoftware/invenio-base