Support default pid limits in containers.conf

Starting With podman 2.X the default pids-limits has been halved from
4096 to 2048:
$ rpm -q podman && podman run --rm -it --net=host --name 'pids' edecd409281d sh -c 'cat /sys/fs/cgroup/pids/pids.max'
podman-2.2.1-3.module+el8.3.1+9392+c5f6d096.x86_64
2048

With podman-1.6.4 the global default pid-limits was hardcoded to 4096
and we had no way to tweak it.

With podman 2.X it is possible to override this in
/etc/containers/containers.conf with the pids_limit setting inside
[containers] in the /etc/containers/containers.conf ini-file:
$ cat /etc/containers/containers.conf
[containers]
pids_limit=6666

$ podman run --rm -it --net=host --name 'pids' edecd409281d sh -c 'cat /sys/fs/cgroup/pids/pids.max'
6666

By adding this we keep the older 4096 default so we do not regress and
at the same time we allow an operator to override this globally.

Related-Bug: #1915122

Change-Id: Id5d5fb9d20c0295763c78171190b9eda13508617

tripleo_ansible/roles/tripleo_podman/defaults/main.yml

@@ -76,3 +76,4 @@ tripleo_podman_default_network_config:
 #   - prefix: registry.fedoraproject.org
 #     blocked: true
 tripleo_podman_registries: []
+tripleo_container_default_pids_limit: 4096

tripleo_ansible/roles/tripleo_podman/tasks/tripleo_podman_install.yml

@@ -61,3 +61,15 @@
         group: root
         setype: etc_t
         mode: '0644'
+
+    - name: Write containers.conf
+      ini_file:
+        path: /etc/containers/containers.conf
+        owner: root
+        group: root
+        setype: etc_t
+        mode: '0644'
+        create: true
+        section: containers
+        option: pids_limit
+        value: "{{ tripleo_container_default_pids_limit }}"