Feature request for the API: creating and updating backup configurations.

Right now the API can list and get backup configurations (GET /api/user/backup-configurations), and create database backups that use one. But a new configuration can only be added in the dashboard.

Our use case: every customer gets their own S3 bucket (Cloudflare R2) with its own credentials, so backups and costs stay separated per customer. We create the bucket and credentials automatically through the Cloudflare API. The only manual step left is adding the backup configuration in Ploi.

What would help:

• POST /api/user/backup-configurations (type, label, key, secret, region, bucket, endpoint, path style)
• PATCH and DELETE for the same, so credentials can be rotated and removed
• Ideally a scope for it, e.g. backup-configurations-create

With that, onboarding a new server with backups is fully automated through the API.