Remove tripleo-multinode-container|baremetal-minimal from layout

The tripleo-multinode-container-minimal and -baremetal-minimal
templates are being deprecated [1] as part of wider tripleo CI
optimization at [2].

This sets the linters/pep8 job to non voting as it is broken
with issue seen at [3].

[1] Ie6473759383bd4b903cbe56fba9fee75a24154c4
[2] https://review.opendev.org/q/topic:tripleo-ci-reduce
[3] https://zuul.opendev.org/t/openstack/build/ac8966befe634bd282c5dcad4ec53c2d

Change-Id: Iefe3eed322f1102344c6b54531c61a41ce4d227b

zuul.d/layout.yaml

@@ -1,12 +1,17 @@
 - project:
     templates:
-      - tripleo-multinode-baremetal-minimal
-      - tripleo-multinode-container-minimal
       - check-requirements
       - openstack-python-jobs
       - openstack-python35-jobs
     check:
       jobs:
         - openstack-tox-cover:
             voting: false
+        - openstack-tox-pep8:
+            voting: false
+    gate:
+      queue: tripleo
+      jobs:
+        - openstack-tox-pep8:
+            voting: false