Add subnet tests for extra attributes

* Tests added for ipv4/6
test_create_delete_subnet_with_allocation_pools
test_create_delete_subnet_with_gw_and_allocation_pools
test_create_delete_subnet_with_host_routes_and_dns_nameservers
test_create_delete_subnet_with_dhcp_enabled
test_update_subnet_gw_dns_host_routes_dhcp
test_create_delete_subnet_all_attributes

* Adds helper to create/verify/delete subnet
* Adds helper to delete network

Implements: bp subnet-extra-attributes

Change-Id: I7c1b00f4fad797eb5dd904f1123b5bcd5e5af649
Migrate orchestration API tests to resource_* fixtures

Partially-implements bp resource-cleanup

Change-Id: I58b5f9f17d166c762a1091f4ecb2c560bff8e977
Migrate queuing API tests to resource_* fixtures

Partially-implements bp resource-cleanup

Change-Id: I5c2773e1e0d475dcbd77007121a33ae06a436c22
Migrate telemetry API tests to resource_* fixtures

Partially-implements bp resource-cleanup

Change-Id: I47e007ef70b79044d78c08b07b222183e1025f70
Merge "Add subnet tests for extra attributes"
Drop OfficialClientManager from tenant isolation

Scenario tests use the tempest clients, so drop support for
OfficialClientManager from the tenant isolation classes.

Change-Id: I84638210043d376b4f4025a69751536651991293
Partially-implements: bp:tempest-client-scenarios
Merge "Migrate orchestration API tests to resource_* fixtures"
Merge "Migrate queuing API tests to resource_* fixtures"
Merge "Drop OfficialClientManager from tenant isolation"
Merge "Migrate telemetry API tests to resource_* fixtures"
Merge branch 'master' of https://github.com/openstack/tempest