CLN: holdinvoice archived in favor of hold

[daywalker90]

Hey, i have archived https://github.com/daywalker90/holdinvoice because https://github.com/BoltzExchange/hold is very close in functionality and i don't want to waste dev hours on duplicate work and they are a company with more ressources.

Key differences:

• hold does holdinvoices more properly: they do not require a preimage to be known upon creating a holdinvoice
• you are responsible for the htlc's not causing a force close

[KoalaSat]

Thanks for the heads up @daywalker90 , I'll mark this issue for anybody willing to help with the migration