What would you like to be added:

Currently the target flags --garden, --project, --shoot, --seed, --control-plane are available for the target and all of its subcommands.

Clarify if

1. we want to keep it this way and allow sth. like target project myproject --garden mygarden OR
2. the target flags should only be available if none of the target-subcommand is used (target --garden mygarden)
   3) only target flags with a higher specificity are allowed. So target project myproject --shoot myshoot would be ok but not target project myproject --garden mygarden would not.

Why is this needed:

follow up for #85