Revert "HADOOP-19197. S3A: Support AWS KMS Encryption Context (#7193)"

This reverts commit eb656c016facfa1b60f2e9e4d95ebd5ca1b1bc0a.

This was done because the writable/serializable class
    org.apache.hadoop.fs.s3a.auth.delegation.EncryptionSecrets
is no longer wire-compatible once context attributes
are included.
18 files changed