Right now just s3, I hope people will add more with PRs

I probably won't be able to check it out until the weekend. 😭. Too much to do on my day job...

This reminds me, I'm not using an S3-compatible solution for backup. So far, I've had to set the backup provider to a placeholder value and the interval to a large number to avoid the '🚫 We only support AWS at this time' errors. Is there a better way to disable backups through the settings? Otherwise, I'm happy to contribute a flag to disable backups altogether.