Update minio settings, enable direct upload

What changed:

• enable direct_upload in object storage; this setting will be the default in GitLab 15.0 and we should make sure GCK works with this enabled
• update MinIO settings to catch up with changes and deprecations in recent releases

I tested DU by dropping a file into an issue comment; it was uploaded as follows:

workhorse_1         | time="2022-04-27T07:21:16Z" level=info msg="saved file" client_mode=s3_multipart copied_bytes=119532 correlation_id=01G1MYAJKY748KGQRSTEHT2X9N is_local=false is_multipart=true is_remote=true remote_id=1651044076-91-0001-6104-b037e4b3cefe215a8519412f54e2e188 remote_temp_object=tmp/uploads/1651044076-91-0001-6104-b037e4b3cefe215a8519412f54e2e188 temp_file_prefix=C64_TrueType_v1.2.1-STYLE.zip

• client_mode=s3_multipart means it was using WH's built-in S3 client instead of a pre-signed URL
• is_local=false means this isn't a disk-buffered controller upload
• is_remote=true means it is going straight into OS

So seems to be working.