blip-0039: BOLT 11 Invoice Blinded Path Tagged Field

[ellemouton]

This bLIP defines a new tagged field, b, for the payment invoice encoding described by BOLT 11 which can be used to communicate encoded blinded path information to the payer of the invoice. It also introduces a new feature bit for the I context to indicate the presence of the new field in an invoice.

Delving Post: https://delvingbitcoin.org/t/blip-bolt-11-invoice-blinded-path-tagged-field/991 Implementation: https://github.com/lightningnetwork/lnd/pull/8752