Configure logLevel in ClusterFluentBitConfig

[dennis-ge]

Is your feature request related to a problem? Please describe.

In the Helm Chart, when setting Kubernetes to true, the default ClusterFluentBitConfig does not configure the spec.service.logLevel and hence the info log level is applied for the FluentBit pods.

Describe the solution you'd like

I would like to configure the logLevel via the helm chart, e.g., setting it to warning. There is already an option for fluentd in the helm chart: https://github.com/fluent/fluent-operator/blob/master/charts/fluent-operator/values.yaml#L371. I suggest adopting the same approach there, i.e, setting it to "" and then checking in the template:

fluent-operator/charts/fluent-operator/templates/fluentd-fluentd.yaml

Line 34 in 4233bb7

logLevel: {{ .Values.fluentd.logLevel }}

Additional context

I think this is quite straightforward, I am also happy to provide a PR if this is accepted.