CMO e2e: some containers need securityContext.capabilities settings

Our CMO e2e tests create several containers besides the standard CMO deployment. These pods do currently not set any security context capabilities. Currently this creates a warning like so:

W0705 08:35:38.590283 15206 warnings.go:70] would violate PodSecurity "restricted:v1.24": allowPrivilegeEscalation != false (container "alertmanager-webhook-e2e-testutil" must set securityContext.allowPrivilegeEscalation=false), unrestricted capabilities (container "alertmanager-webhook-e2e-testutil" must set securityContext.capabilities.drop=["ALL"]), runAsNonRoot != true (pod or container "alertmanager-webhook-e2e-testutil" must set securityContext.runAsNonRoot=true), seccompProfile (pod or container "alertmanager-webhook-e2e-testutil" must set securityContext.seccompProfile.type to "RuntimeDefault" or "Localhost")

We should be proactive and set security capability contraints. From this run this seems to impact the following pods/containers:

• alertmanager-webhook-e2e-testutil
• prometheus-example-app

Both are used more then once.

Relevant docs: https://docs.openshift.com/container-platform/4.10/authentication/managing-security-context-constraints.html#security-context-constraints-about_configuring-internal-oauth