To avoid regression, we could initially just add these as command aliases to grin-wallet. So we would have aliases
request-bill -> send
offer-bill -> receive
accept-bill -> finalize
for SRS/regular flow, and
request-payment -> invoice
offer-payment -> pay
accept-payment -> finalize
for RSR/invoice flow. Everything will keep working as is, but users have the option to start using a more consistent system of step names.