Add flag `-y` that says `Yes` to every prompt

[cmichi]

As a shortcut for e.g. --skip-confirm --skip-dry-run.

[ltfschoen]

yes, great thinking

an example would be running:

cargo contract instantiate --suri //Bob --constructor new  --args true --execute

which outputs the following

 Dry-running new (skip with --skip-dry-run)
    Success! Gas required estimated at Weight(ref_time: 328662761, proof_size: 0)
Confirm transaction details: (skip with --skip-confirm)
 Constructor new
        Args true
   Gas limit Weight(ref_time: 328662761, proof_size: 0)
Submit? (Y/n): Y

so you have to manually enter Y for it to actually execute, or also use the option --skip-confirm for it to automatically skip