Show takes for hotkey per subnet

[gztensor]

Branch: dynamic

Getting takes for hotkey per subnet: The root list_deleagtes command didn't look right when it displayed takes for all subnets (they don't fit in a line), so it was made to display either 18% if the delegate take was default for all subnets or "custom" if it was not, but the actual take is not visible in this case. We need a way to display the take for the delegates. For that a new command needs to be added root show_takes (naming to be discussed) that will prompt user for the hotkey and then use subtensor.get_delegate_by_hotkey() to retrieve delegate information that includes take vector.

Bonus task: Show the return on investment rate.