Should not be able to cert if wallet balance is 0

Should not be able to cert if wallet doesn't exist.

added p1 label

removed p1 label

added p3 label

In fact, we actualy can certify an inexisting wallet, but this one can't confirm his identity. So the actual comportement of can certify null balance is acceptable for now.

added 0.1.0 label and removed p3 label

added p2 label and removed 0.1.0 label