It's possible that a user might not want the Tor private key to sit on the disk in plaintext (it is a private key after all). So this commit adds a new flag to encrypt the Tor private key on disk using the wallet's seed. When the --tor.encryptkey flag is used, LND will still write the Tor key to the same file, however it will now be encrypted intead of plaintext. This essentially uses the same method to encrypt the Tor private key as is used to encrypt the Static Channel Backup file.
This commit lays the groundwork for enabling the option of encrypting a Tor private key on disk, and removes the onion type parameters from the OnionStore interface methods, since they are unused.
Fixes an issue where an out of order block error occurs in the router. When this occurs, the change uses the chain notifier to catch up on missed blocks and uses those blocks to fully update the routing graph with closed channels. Fixes#4710, #5132
Orbital