Fix[IT]: add domain consistency coverage

[alexander-e1off]

Closes #543

The following changes are introduced to cover domain consistency in integration tests

• Added new optional pytest command line argument:

--domain-consistency={eventual,strong,both}
                      run with domain consistency: <eventual>, strong or both

which is used for tests parameterization to define domain consistency (by default eventual).

• If it is needed to test method for different domain consistencies
  (eventual, strong or both), optional argument domain_urls should
  be passed. It should be used instead of direct using DOMAIN_* and URI_*
  constants (except DOMAIN_BROADCAST/URI_BROADCAST):

    def test_post_message_priority(self, cluster, 
                                   domain_urls: tc.DomainUrls):
        du = domain_urls
        self.producer.open(
            du.uri_priority, flags=['write', 'ack'], succeed=True)
        self.producer.post(
            du.uri_priority, payload=[payload], succeed=True, wait_ack=True)

• When integration test is running, consistency argument is shown in parametrization, e.g.

test_admin_client.py::test_queue_stats[single_node_fsm-eventual_consistency] PASSED
test_admin_client.py::test_queue_stats[single_node_fsm-strong_consistency] PASSED