Port availability zones to core API

Changes:
- Register availability zones API as core API using old link.
- Remove extension code for availability zones.
- Leave rename of API url for future update which will be done with
  bump of microversion after port of all extensions to core API.

Partially implements bp ext-to-core

Change-Id: Ifc75ef2d16121634ad12e5e12960c928e4d24b90
diff --git a/manila_tempest_tests/tests/api/test_availability_zones.py b/manila_tempest_tests/tests/api/test_availability_zones.py
index 7330f41..9176683 100644
--- a/manila_tempest_tests/tests/api/test_availability_zones.py
+++ b/manila_tempest_tests/tests/api/test_availability_zones.py
@@ -24,10 +24,13 @@
         self.assertTrue(len(availability_zones) > 0)
         keys = ("created_at", "updated_at", "name", "id")
         for az in availability_zones:
+            self.assertEqual(len(keys), len(az))
             for key in keys:
                 self.assertIn(key, az)
 
     @test.attr(type=["smoke", "gate"])
-    def test_list_availability_zones_extension(self):
+    def test_list_availability_zones_extension_url(self):
+        # NOTE(vponomaryov): remove this test with removal of availability zone
+        # extension url support.
         azs = self.shares_client.list_availability_zones()
         self._list_availability_zones_assertions(azs)