Migrate TestStampPattern to tempest client

Migrate TestStampPattern to tempest client. The test is currently
disabled in the gate, so this will be tested by adding a temp
patch on top removing the skip.

Partially-implements: bp:tempest-client-scenarios

Change-Id: I42524372ae64121f2e3b58f37b960f8d1bbc8b6a
Migrate database API tests to resource_* fixtures

Partially-implements bp resource-cleanup

Change-Id: Iadb0a985e9ea3567c276a4659948037d39d7b845
Migrate data_processing API tests to resource_* fixtures

Partially-implements bp resource-cleanup

Change-Id: Ife28fc82dfab4262147bc118ed90cb162f462510
Drop autoscaling scenario test

Drop autoscaling scenario test. It has always been skipped, so there
is no loss of test coverage. It takes a very long time to run since
it uses real alarms to perform 4 scaling operations.

See https://review.openstack.org/#/c/122320/.

Change-Id: If37f63565a235c6128566f8f2cd993ed247f0912
Partially-implements: bp/tempest-client-scenarios
Migrate test_load_balancer_basic to tempest client

This patch migrates the load balancer basic ops scenario test from official
client to tempest clients.

It also removes the NeutronRetriever class from the test script

Partially-implements: bp:tempest-client-scenarios

Change-Id: I4f3da202646821671d0e98707031a49973c256b2
Merge "Migrate database API tests to resource_* fixtures"
Merge "Migrate data_processing API tests to resource_* fixtures"
Merge "Migrate TestStampPattern to tempest client"
Merge "Drop autoscaling scenario test"
Merge "Migrate test_load_balancer_basic to tempest client"
Merge branch 'master' of https://github.com/openstack/tempest