[application/connect] simplify connection logic ``application.connect`` now either sets a full featured ``DBAPISession`` to the ``WebRequest`` object or raises ``AuthenticationError``. The creation and usage of a fake DBAPISession is now handled by ``main_handle_request`` when needed. This means that fake DBAPISession are no longer tracked by the session manager and that user are not given anyway to retrieve them for a later request. This fake DBAPISession is still passed to ``core_handle`` because multiple cubes like registration or forgotten password need this behavior. We would like to get ride of it in the future. This clarification of the connection API greatly simplifies ``DBAPISession`` retrieval//creation process opening the way to improvements in this area. Related to #2503918

config['rql-cache-size'] = config['rql-cache-size'] * 10

add_entity_type('CWDataImport')

from cubicweb.schema import CONSTRAINTS, guess_rrqlexpr_mainvars
for rqlcstr in rql('Any X,XT,XV WHERE X is CWConstraint, X cstrtype XT, X value XV,'
                   'X cstrtype XT, XT name IN ("RQLUniqueConstraint","RQLConstraint","RQLVocabularyConstraint"),'
                   'NOT X value ~= ";%"').entities():
    expression = rqlcstr.value
    mainvars = guess_rrqlexpr_mainvars(expression)
    yamscstr = CONSTRAINTS[rqlcstr.type](expression, mainvars)
    rqlcstr.cw_set(value=yamscstr.serialize())
    print 'updated', rqlcstr.type, rqlcstr.value.strip()