Define an option to autocreate prefix on target zpool with subcommand backup

[thorstenspille]

The subcommand backup stops, if the target prefix is not present on the zpool.
By default the program should print a message like The configured prefix was not found on the target zpool. Please ensure you created the prefix and have sufficient permissions..
The workflow with the config option activated could be:

#check if prefix present on zpool
if not exists:
    try:
        # create prefix
    except:
        print (f"Auto-creation of prefix {prefix} on zpool {zpool} on target failed. Please ensure you have sufficient permissions.")