Use presigned URLs from S3 for downloads doesn't work with Google Cloud Storage

[cpswan]

A recent change to upstream:

Breaking: Use presigned URLs from S3 for downloads
This to avoid having to proxy all downloads through filebin, which was too much for filebin.net to handle. A relatively unfortunate consequence is that server side encryption is disabled since decryption of presigned downloads is not possible. This is a breaking change since the nonce column as been removed from the file table in the database schema.

In order to upgrade existing installations, it is possible to drop the nonce column from the file table manually using: ALTER TABLE file DROP COLUMN nonce;

Unfortunately this doesn't work with Google Cloud Storage:

<Error>
<Code>SignatureDoesNotMatch</Code>
<Message>The request signature we calculated does not match the signature you provided. Check your Google secret key and signing method.</Message>
<StringToSign>GET 1624537054 /test-filebin2/eb318d739823cf741ecb8aad8f27266f916ba0561198a949c45ab5f3413fe51d/e27bf9b5dafdddc15b68ba198cc4be3c8c476461f6e2dfada5f976c991ab4388</StringToSign>
</Error>

This means were going to have to work from our point in time fork of upstream for now, and consider whether we want to:

1. Use an AWS S3 bucket for storage
2. Modify the code to work properly with GCS