This includes the new profile fetched_at logic and reaction stats.
When receiving new profiles, nostrdb will record when it was last
received in a new database. This database is a mapping from Pubkey to
timestamp.
You can manually read/write to this table using:
ndb_read_last_profile_fetch
ndb_write_last_profile_fetch
This patch also includes the new reaction counting metadata table. It is
not used yet (but reactions are still counted!)
Changelog-Added: Added reaction counters to nostrdb
Changelog-Added: Record when profile is last fetched in nostrdb