fix: Airflow demo improvements

[adwk67]

This PR fixes:

• replaces cluster-wide permissions with namespace-scoped ones
• replaces minio and mc images from quay.io/minio with ones from docker.io/pgsty/mc
  • this is only provisional and should be replaced with garage as decided here: test(s3): replace MinIO with Garage nifi-operator#1001
• the airflow versions so it uses 3.3.1 (and not 3.1.6 as determined previously by the podOverrides)

And changes:

• the spark sensor such that logs are streamed from the driver and executor pods to the Airflow UI
• N.B. this does not necessitate granting Airflow any extra permissions that it has already anyway to access Spark logs (at whatever level)