Add support for SSE-C encryption on S3

Similarly to https://github.com/duckdb/duckdb-httpfs/pull/3, it would be great to support [server side encryption via customer-provided keys (SSE-C)](https://docs.aws.amazon.com/AmazonS3/latest/userguide/ServerSideEncryptionCustomerKeys.html). It is quite usual for S3 clients to support SSE via both KMS and customer-provided keys.

It could be configured with something like:
```
CREATE SECRET encrypted (
TYPE S3,
PROVIDER config,
SSE_C_KEY ' base64-encoded encryption key'
);
```