Stand alone Subscription Filter CRD for ACK Cloudwatch logs controller

[jas-nik]

Is your feature request related to a problem?
Currently subscription filter is part of the ACK cloudwatch logs controller spec. For pre-existing cloudwatch loggroups that were created external to ACK cloudwatch logs controller (created as a part of Lambda or EKS control plane logging for example), we will need to use AdoptedResource to import cloudwatch log group and update the log group subscription filters spec.

Describe the solution you'd like
A standalone crd for subscription filter in ACK cloudwatch logs controller makes it GitOps friendly.

Describe alternatives you've considered
We include an aws-cli job that is part of our ack charts that uses IRSA to create the necessary subscriptionFilter configuration.