…its own package called lnencrypt

The functions inside of the crypto.go file in chanbackup (like EncryptPayloadToWriter and DecryptPayloadFromReader) can be used by a lot of things outside of just the chanbackup package. We can't just reference them directly from the chanbackup package because it's likely that it would generate circular dependencies. Therefore we need to move these functions into their own package to be referenced by chanbackup and whatever new functionality that needs them

This commit adds support in lnd to encrypt the TLS private key on disk with the wallet's seed. This obviously causes issues when the wallet is locked. So for the WalletUnlocker RPC we generate ephemeral TLS certificates with the key stored in memory. This feature is enabled with the --tlsencryptkey flag.

… from the beginning