Add wildcard namespace selector for clusterLogForwarding.namespace_groups

[haasad]

Context

clusterLogForwarding.namespace_groups currently requires a list of namespaces. It would be convenient if namespaces could be selected based on naming pattern, e.g. *-dev. This would reduce the effort of manually keeping the namespace list up to date in the config if projects are added/removed.

Implementation idea

• expose label selector since wildcards are not possible

[DebakelOrakel]

That is not possible with the ClusterLogForwarding CR.
We should instead figure out, how LogForwarding in a namespace works.

[DebakelOrakel]

However, there is another interessting hook:

❯ k explain clusterlogforwarder.spec.inputs.application.selector
GROUP:      logging.openshift.io
KIND:       ClusterLogForwarder
VERSION:    v1

FIELD: selector <Object>

DESCRIPTION:
    Selector for logs from pods with matching labels. Only messages from pods
    with these labels are collected. If absent or empty, logs are collected
    regardless of labels.

FIELDS:
  matchLabels   <map[string]string>
    matchLabels is a map of {key,value} pairs. A single {key,value} in the
    matchLabels map is equivalent to an element of matchExpressions, whose key
    field is "key", the operator is "In", and the values array contains only
    "value". The requirements are ANDed.

[DebakelOrakel]

Above PR allows for configuration of features like matchLabels on inputs.
Does that solve your issue?