Rely on get_formats() rather than just the static plugin data in the 'status' API call. This removes the need for the special casing for LVM storages without the 'snapshot-as-volume-chain' option. It also fixes the issue that the 'format' storage configuration option to override the default format was previously ignored there. Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>