[ci] Define/enable magnum-tempest-plugin-tests-api

This commit defines magnum-tempest-plugin-tests-api job which uses the
new devstack-tempest as parent job recommended for running
Tempest tests in Zuul v3.

Story: 2007561
Task: 39470

Depends-on: https://review.opendev.org/#/c/721265

Change-Id: If7b77099a90d405e248c80777fa5e8b3612b5c2e

.zuul.yaml

@@ -2,5 +2,66 @@
     templates:
       - check-requirements
       - tempest-plugin-jobs
+    check:
+      jobs:
+        - magnum-tempest-plugin-tests-api
     gate:
       queue: magnum
+      jobs:
+        - magnum-tempest-plugin-tests-api
+
+- job:
+    name: magnum-tempest-plugin-tests-api
+    parent: magnum-tempest-plugin-base
+    vars:
+      tox_envlist: all
+      tempest_test_regex: ^magnum_tempest_plugin.tests.api
+      tempest_black_regex: ^magnum_tempest_plugin.tests.api.v1.test_cluster.ClusterTest.test_create_list_sign_delete_clusters
+      devstack_local_conf:
+        test-config:
+          $TEMPEST_CONFIG:
+            magnum:
+              image_id: fedora-coreos-31.20200323.3.2-openstack.x86_64
+              nic_id: public
+              keypair_id: default
+              flavor_id: ds2G
+              master_flavor_id: ds2G
+              copy_logs: true
+
+- job:
+    name: magnum-tempest-plugin-base
+    description: |
+      Magnum functional tests base layer
+    parent: devstack-tempest
+    required-projects:
+      - openstack/magnum
+      - openstack/python-magnumclient
+      - openstack/heat
+      - openstack/barbican
+      - openstack/magnum-tempest-plugin
+    vars:
+      tempest_plugins:
+        - magnum-tempest-plugin
+      devstack_localrc:
+        USE_PYTHON3: true
+        MAGNUM_GUEST_IMAGE_URL: https://builds.coreos.fedoraproject.org/prod/streams/stable/builds/31.20200323.3.2/x86_64/fedora-coreos-31.20200323.3.2-openstack.x86_64.qcow2.xz
+        MAGNUM_IMAGE_NAME: fedora-coreos-31.20200323.3.2-openstack.x86_64
+      devstack_plugins:
+        magnum: https://opendev.org/openstack/magnum
+        heat: https://opendev.org/openstack/heat
+        barbican: https://opendev.org/openstack/barbican
+      devstack_services:
+        # Disable swift and dependent c-bak service to support upload of .qcow2.xz image in the gate
+        s-account: false
+        s-container: false
+        s-object: false
+        s-proxy: false
+        c-bak: false
+    irrelevant-files:
+      - ^.*\.rst$
+      - ^api-ref/.*$
+      - ^doc/.*$
+      - ^specs/.*$
+      - ^install-guide/.*$
+      - ^releasenotes/.*$
+      - ^dockerfiles/.*$