Add check for pod being controlled by other resource

[marians]

A pod that is not controlled by another resource is not resilient to nodes being terminated and other common cluster disruptions. Hence this PR adds a check with severity=2 to see whether a pod is controlled by any resource.

Preview

The pod has been launched using this command:

kubectl run marian-toolbox \
    --namespace marian \
    --stdin --tty \
    --restart Never \
    --rm \
    --image quay.io/marian/toolbox

TODO

• Currently it looks as if I cannot exclude this check using this config:

popeye:
  excludes:
    v1/pods:
      - name: rx:marian
        codes:
          - 208

Any advice would be welcome.

[derailed]

@marians Thank you for this PR! Setting the code exclusion in the spinach file seems to work correctly.