Tests: Add missing file provider tests

[pozylon]

GridFS:

• Sign Upload
• Upload with signed Stream (REST Handler, tested)
• Upload from URL (tested with bulk import)
• Sign Download (private)
• Download from Stream (REST Handler)
• Remove Binaries

Minio:

• Sign Upload
• Upload with signed Stream (directly to s3-compat bucket) & REST Handler for Webhook
• Upload from URL
• Sign Download
• Download from Stream (directly from s3-compat bucket)
• Remove Binaries

[pozylon]

Actually this is already done mostly for the gridfs plugin, minio tests can be postponed to v5