S3: ability to force server-side encryption

@daniel.pan we are interested as well in Server Side Object Storage encrpytion.

Our plattform provider (not AWS) Supports SSE-C over the nativ AWS S3 API.
Is there any Posibility to add the required settings to the seafile config.

Different S3 Encryption Types: Amazon S3 Server-Side Encryption Types - CMKs Stored in AWS KMS (SSE-KMS), Amazon S3-managed encryption keys (SSE-S3), customer-provided encryption keys (SSE-C)

Reference SSE-C: Using server-side encryption with customer-provided keys (SSE-C) - Amazon Simple Storage Service
Reference SSE-KMS: Using server-side encryption with AWS KMS keys (SSE-KMS) - Amazon Simple Storage Service

Thank you very much for check this feature.