v1.6.2-FEECREDIT-7

What's Changed

• Minor API improvements for sending/receiving payments by @pm47 in #619
• Build onion messages by @thomash-acinq in #623
• Incoming blinded payments by @thomash-acinq in #621
• Rework channel reestablish by @pm47 in #629
• Refactor onion payload validation by @t-bast in #631
• Add more blinded payment onion tests by @t-bast in #632
• Generate default deterministic offer by @t-bast in #626
• Add OfferManager by @thomash-acinq in #624
• Increase maximum cltv_expiry_delta by @t-bast in #635
• Improve bolt11 serialization performance by @sstone in #637
• More detailed error when HTLC could not be sent by @t-bast in #634
• Add toString to payment part failures by @pm47 in #638

Full Changelog: v1.6.2-FEECREDIT-6...v1.6.2-FEECREDIT-7