In this commit, we add the various sqlc queries that we need in order
to implement the following V1Store methods:
- AddLightningNode
- FetchLightningNode
- HasLightningNode
- AddrsForNode
- DeleteLightningNode
- FetchNodeFeatures
These are implemented by SQLStore which then lets us use the SQLStore
backend for the following unit tests:
- TestNodeInsertionAndDeletion
- TestLightningNodePersistence
