Restructure layout for periodic, experimental and tox jobs

Following changes are done to make future changes
to these job layouts efficient:-
- Move periodic, experimental and tox jobs overrides
  to seperate project-template and file. This will
  avoid running other jobs when changes are done
  to periodic and experimental pipelines(as these
  pipelines do not run on new patch sets).
- Update irrelevant-files for tox jobs so that those
  can be skipped on file changes which these jobs
  do not test.

Also drop comment for TripleO job as that's no
longer valid after moving those jobs to periodic
pipeline.

Change-Id: Ib50875acd872d8aaecc7c874a1429788c6bf2445
(cherry picked from commit 22f1c99453)
Conflicts: zuul.d/project.yaml

zuul.d/job-templates.yaml

@@ -0,0 +1,61 @@
+- project-template:
+    name: neutron-tox-override-jobs
+    check:
+      jobs:
+        - openstack-tox-py36:  # from openstack-python3-xena-jobs template
+            timeout: 3600
+            irrelevant-files:  &irrelevant-files
+              - ^.*\.conf\.sample$
+              - ^.*\.rst$
+              - ^doc/.*$
+              - ^neutron/locale/.*$
+              - ^neutron/tests/fullstack/.*$
+              - ^neutron/tests/functional/.*$
+              - ^releasenotes/.*$
+              - ^setup.cfg$
+              - ^tools/.*$
+              - ^vagrant/.*$
+              - ^devstack/.*$
+              - ^playbooks/.*$
+              - ^roles/.*$
+              - ^rally-jobs/.*$
+              - ^zuul.d/(?!(job-templates)).*\.yaml
+        - openstack-tox-py38: # from openstack-python3-xena-jobs template
+            timeout: 3600
+            irrelevant-files:  *irrelevant-files
+        - openstack-tox-cover:  # from openstack-cover-jobs template
+            timeout: 4800
+            irrelevant-files:  *irrelevant-files
+    gate:
+      jobs:
+        - openstack-tox-py36:  # from openstack-python3-xena-jobs template
+            timeout: 3600
+            irrelevant-files:  *irrelevant-files
+
+- project-template:
+    name: neutron-experimental-jobs
+    experimental:
+      jobs:
+        - neutron-functional-with-uwsgi-fips
+        - neutron-fullstack-with-uwsgi-fips
+        - neutron-ovs-tempest-fips
+        - neutron-ovn-tempest-ovs-release-fips
+        - neutron-ovn-grenade-multinode
+        - neutron-ovn-tempest-with-uwsgi-loki
+
+- project-template:
+    name: neutron-periodic-jobs
+    periodic:
+      jobs:
+        - neutron-functional
+        - neutron-fullstack
+        - neutron-ovn-tempest-postgres-full
+        - neutron-ovn-tempest-mariadb-full
+        - neutron-ovn-tempest-ovs-release
+        - neutron-ovn-tempest-ovs-release-ipv6-only
+        - devstack-tobiko-neutron:
+            voting: true
+        - ironic-tempest-ipa-wholedisk-bios-agent_ipmitool-tinyipa
+        - openstacksdk-functional-devstack-networking
+        - neutron-linuxbridge-tempest-plugin-scenario-nftables
+        - neutron-ovs-tempest-plugin-scenario-iptables_hybrid-nftables

zuul.d/project.yaml

@@ -12,6 +12,9 @@
       - periodic-stable-jobs
       - check-requirements
       - release-notes-jobs-python3
+      - neutron-experimental-jobs
+      - neutron-periodic-jobs
+      - neutron-tox-override-jobs
     check:
       jobs:
         - neutron-functional-with-uwsgi
@@ -32,12 +35,6 @@
         #    voting: false
         - neutron-ovn-rally-task:
             voting: false
-        - openstack-tox-py36:  # from openstack-python3-xena-jobs template
-            timeout: 3600
-        - openstack-tox-py38:  # from openstack-python3-xena-jobs template
-            timeout: 3600
-        - openstack-tox-cover:  # from openstack-cover-jobs template
-            timeout: 4800
     gate:
       jobs:
         - neutron-functional-with-uwsgi
@@ -49,30 +46,4 @@
         # will be fixed
         # - neutron-ovs-grenade-dvr-multinode
         - neutron-ovn-tempest-ipv6-only
-        - openstack-tox-py36:  # from openstack-python3-xena-jobs template
-            timeout: 3600
         #- neutron-ovn-rally-task
-
-    experimental:
-      jobs:
-        - neutron-functional-with-uwsgi-fips
-        - neutron-fullstack-with-uwsgi-fips
-        - neutron-ovs-tempest-fips
-        - neutron-ovn-tempest-ovs-release-fips
-        - neutron-ovn-grenade-multinode
-        - neutron-ovn-tempest-with-uwsgi-loki
-
-    periodic:
-      jobs:
-        - neutron-functional
-        - neutron-fullstack
-        - neutron-ovn-tempest-postgres-full
-        - neutron-ovn-tempest-mariadb-full
-        - neutron-ovn-tempest-ovs-release
-        - neutron-ovn-tempest-ovs-release-ipv6-only
-        - devstack-tobiko-neutron:
-            voting: true
-        - ironic-tempest-ipa-wholedisk-bios-agent_ipmitool-tinyipa
-        - openstacksdk-functional-devstack-networking
-        - neutron-linuxbridge-tempest-plugin-scenario-nftables
-        - neutron-ovs-tempest-plugin-scenario-iptables_hybrid-nftables