Add S3 SSE KMS key and bucket key encryption

[juliusknorr]

Originally proposed by @tsdicloud this is the rebased version of #26899 with pulling the changes from https://github.com/nextmcloud/server/compare/master..s3fragment without the already merged parts from #27877

• Add option to set a SSE KMS id and enable usage of bucket key encryption
• Replace 'verify_bucket_exists' with 'autocreate' as documented in https://docs.nextcloud.com/server/latest/admin_manual/configuration_files/primary_storage.html#simple-storage-service-s3 which is also used in other object storage implementations as described in [S3] 'verify_bucket_exists' instead of 'autocreate' in S3 config #26093
• Double check with working patch
  • https://github.com/nextmcloud/server/blob/47c00d0724ec118076ea6fcd102d62112a6a8744/lib/private/Files/ObjectStore/S3ConnectionTrait.php
  • https://github.com/nextmcloud/server/blob/47c00d0724ec118076ea6fcd102d62112a6a8744/lib/private/Files/ObjectStore/S3ObjectTrait.php

[juliusknorr]

🏓 for review

[artonge]

SseKmsPutParameters is placed under a config property, SseKmsGetParameters is not, is this right?

[juliusknorr]

Closing this for now as there is no current demand. This can be picked up to finish anytime of course.