[Feature Request] - Accept different sighash types

[polespinasa]

I tried (with sparrow as software wallet) to build and sign transactions with the seedsigner with different sighash types like:
Single, None, Single + Anyonecanpay, etc.

All of them give an error so I assume this is not implemented. I think this would be a nice feature to have and would open the doors to do many more things with seedsigner.