[UI] Show storage in the schedules list and in the backups list

The note “Maximum 3 schedules for PostgreSQL“ is not exactly correct. The truth is that the PG can’t use more than 3 different storages in schedules and in the existing backups (in total).

To make it transparent for the user which storages are used in the schedules and the existing backups, we need to show the storages in the list view for both schedules and backups