Backup to AWS S3 using temporary credentials

**Describe the unexpected behaviour**
Backup and restore using AWS S3 does not work when using temporary credentials.

**Additional context**
Currently it's not possible to trigger a backup query to AWS S3 when using temporary credentials, such as when assuming a role. That's because temporary credentials have another token, the session token. This token must be passed to AWS alongside the access key id and secret access key.

A possible solution would be to extend the `S3` disk definition to allow for the third token. An alternative solution would be to allow these credentials to be passed in to the `S3` endpoint itself in form of query parameters. This is the way other databases such as CockroachDB do it.