Add TripleO Jobs back

This patch also adds dependency to the linters jobs to save the CI.

Change-Id: I2ce56ddc1841bba78905a8460e26c541602f75df
Signed-off-by: Gael Chamoulaud (Strider) <gchamoul@redhat.com>

zuul.d/layout.yaml

@@ -5,7 +5,25 @@
       - openstack-lower-constraints-jobs
     check:
       jobs:
-        - openstack-tox-linters
+      - openstack-tox-linters: &tripleo-linters
+          nodeset: centos-8
+      - tripleo-ci-centos-8-containers-multinode: &containers_multinode
+          dependencies: &deps
+            - openstack-tox-linters
+          files: &containers_files
+          - ^validations_libs/.*
+          irrelevant-files: &irrelevant_scenario_files
+          - .*.md$
+          - .*.rst$
+          - .*.txt$
+          - .*.ini$
+          - ^validations_libs/tests/.*
+      - tripleo-ci-centos-8-standalone: &basic_standalone
+          dependencies: *deps
+          files: *containers_files
+          irrelevant-files: *irrelevant_scenario_files
     gate:
       jobs:
-        - openstack-tox-linters
+      - openstack-tox-linters: *tripleo-linters
+      - tripleo-ci-centos-8-containers-multinode: *containers_multinode
+      - tripleo-ci-centos-8-standalone: *basic_standalone