backup command (realms)

basically allows you to create backups on command, so for example if you are going to do something risky and it might destroy your stuff, and if it does you want to be able to load a backup. you can use this command to create a backup,  instead of hoping there is a recent backup. you can name this backup so you can easily distinguish it from auto backups. the command syntax would be /backup <backupname:string> 

only the realm owner would be able to use this