LND: PR 11061 from bitromortac merged by yyforyongyu

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bolt12: add Merkle tree and BIP-340 message signatures by bitromortac · Pull Request #11061 · lightningnetwork/lnd
Part of #10736. Based on #11001.
Adds Merkle tree construction over TLV records (MerkleRoot) and BIP-340 Schnorr message signatures (signMessage, v...