accept "binary/octet-stream" content-type

[ryan-williams]

S3 defaults (some?) files to content-type: binary/octet-stream, and datasette-lite was giving a cryptic "That url could not be loaded" alert.

This adds binary/octet-stream to the list of recognized content-types, as well as a console.warn when an unrecognized content-type is encountered.

[Lewiscowles1986]

You can override the mime type header for pre-signed URL's in AWS S3

s3.generate_presigned_url(
    "get_object",
    Params={
        "Bucket": "my-bucket",
        "Key": "file.ext",
        "ResponseContentType": "application/octet-stream"
    },
    ExpiresIn=3600
)

This would bypass the non-standard header you are getting.

[Lewiscowles1986]

being able to override this if you host you own instance doesnt seem like the worlds worst option either. If the PR were to pivot to that, I think it would make datasette-lite more pluggable