Add two signing examples to showcase signing a simple one input two
output transaction using both segwit v0 outputs and taproot outputs.
This patch is the result of the recent rust-bitcoin TABConf workshop,
wit bug fix by Sanket, updated to use APIs from tip of master branch.
This code, depending on v0.30.0 is what is being introduced to the
cookbook at the moment.
Tobin C. Harding