feat: Support arbitrarily setting privileged: true for runner container

[mumoshu]

You can now override the securityContext.privileged per container in both RunnerDeployment and RunnerSet, by specifying it in the containers field for the specifically named container.

In case you'd like to run privileged operations from within your Actions workflow jobs, you'd want to just enable privileged on the runner container:

kind: RunnerDeployment
spec:
  template:
    spec:
      containers:
      - name: runner
        securityContext:
          privileged: true

The default privileged value for the runner container is false as you may know, but the above setting overrides it to true.

To be precise, you were already able to imply privileged: true for the runner container by enabling dockerdWithinRunnerContainer. But that implies you still run dockerd within the runner container, which can be unnecessary depending on your use-case. That's where this new setting comes handy.

Note that you can also utilize the same pattern in RunnerSet, too.

kind: RunnerSet
spec:
  template:
    spec:
      containers:
      - name: runner
        securityContext:
          privileged: true

In case you'd like to disable docker (the docker sidecar) at all, you'd need to set the existing dockerEnabled too, under spec.template.spec for RunnerDeployment and under spec for RunnerSet.

kind: RunnerDeployment
spec:
  template:
    spec:
     dockerEnabled: false
      containers:
      - name: runner
        securityContext:
          privileged: true

kind: RunnerSet
spec:
  dockerEnabled: false
  template:
    spec:
      containers:
      - name: runner
        securityContext:
          privileged: true

Resolves #1282

[toast-gear]

LGTM