This is inspired by the work of
v0l (https://github.com/v0l/nostr-rs-relay/).
A new trait abstracts the storage layer with an async API. Rusqlite
is still used with worker threads, but this allows for Postgresql or
other backends to be used.
There may be bugs, this has not been rigorously tested.
This adds a new configurable feature to restrict event publishing to
only users with NIP-05 verified metadata. Domains can be whitelisted
or blacklisted. Verification expiration and schedules are
configurable.
This upgrades the database to add a table for tracking verification
records.
