Database Backup interval field should not be displayed to clients with limit_backup

Summary

Since commit 6883d165 the interface/web/sites/templates/database_edit.htm form allows user to define a "Backup interval". I believe this field should not be displayed for users or clients with limit_backup, because either :

• it allows them to configure backups, which should be disabled,
• or it make them think they can configure backups.

Proposed fix

I think this field should be hidden for users that does not have access to the "Backup" tab in websites (lines 89 to 98 in interface/web/sites/form/web_vhost_domain.tform.php).

Thank you.