Specify securityContext for cert-manager (#9404)

On hardening environments, cert-manager pods could not be created
from the corresponding deployments. This adds the securityContext
to solve the issue.

roles/kubernetes-apps/ingress_controller/cert_manager/templates/cert-manager.yml.j2

@@ -870,6 +870,11 @@ spec:
                 fieldPath: metadata.namespace
           securityContext:
             allowPrivilegeEscalation: false
+            capabilities:
+              drop: ['ALL']
+            runAsNonRoot: true
+            seccompProfile:
+              type: RuntimeDefault
 {% if cert_manager_tolerations %}
       tolerations:
         {{ cert_manager_tolerations | to_nice_yaml(indent=2) | indent(width=8) }}
@@ -944,6 +949,11 @@ spec:
             protocol: TCP
           securityContext:
             allowPrivilegeEscalation: false
+            capabilities:
+              drop: ['ALL']
+            runAsNonRoot: true
+            seccompProfile:
+              type: RuntimeDefault
           env:
           - name: POD_NAMESPACE
             valueFrom:
@@ -1040,6 +1050,11 @@ spec:
             failureThreshold: 3
           securityContext:
             allowPrivilegeEscalation: false
+            capabilities:
+              drop: ['ALL']
+            runAsNonRoot: true
+            seccompProfile:
+              type: RuntimeDefault
           env:
           - name: POD_NAMESPACE
             valueFrom: