Add storage_options configuration to support S3 server side encryption headers

gitlab-org/omnibus-gitlab!4469 (merged) added support to Omnibus for a storage_options configuration section:

object_store:
  connection: {}
  storage_options:
    server_side_encryption: aws:kms
    server_side_encryption_kms_key_id: arn:s3:xxxx
  objects:
    ...

Documentation for this feature is in gitlab-org/gitlab!39282 (diffs).

/cc: @ghickey