Fix linter errors and add lint skip list

Make centos-8 job non voting, nspawn requries btrfs which is not
available on centos-8

Change-Id: Ib013981138209e56f1a0741d15bfe32dcd48702b

.ansible-lint

@@ -0,0 +1,4 @@
+warn_list:
+  - '204'  # Lines should be no longer than 160 chars
+  - '208'  # File permissions unset or incorrect
+  - '701'  # meta/main.yml should contain relevant info

meta/main.yml

@@ -30,7 +30,7 @@ galaxy_info:
     - name: EL
       versions:
         - 7
-  categories:
+  galaxy_tags:
     - cloud
     - nspawn
     - container

zuul.d/project.yaml

@@ -19,3 +19,11 @@
       - openstack-ansible-role-jobs
       - publish-openstack-docs-pti
       - release-notes-jobs-python3
+    check:
+      jobs:
+        - openstack-ansible-functional-centos-8:
+            voting: false
+    gate:
+      jobs:
+        - openstack-ansible-functional-centos-8:
+            voting: false