cmd/k8s-operator,k8s-operator: Add TSRecorder CRD + controller

[tomhjp]

Deploys tsrecorder images to the cluster for use with kubectl exec session recording. S3 storage is not yet implemented.

Example CR:

apiVersion: tailscale.com/v1alpha1
kind: TSRecorder
metadata:
  name: rec
spec:
  tags:
  - tag:k8s-recorder
  enableUI: true
  storage:
    disk:
      path: /data/recordings

Updates #13298

Still todo:

• [ ] Unit tests
• [ ] e2e test (in a separate branch)
• [ ] More manual testing
• [ ] S3 storage
• [ ] Review the design decisions and other remainders called out in TODOs