Always create a common tracker pattern during mapping

When neither pattern nor domain matching finds an existing common
tracker pattern, upsert one with no third party association and a
lower confidence (0.5) so every seen pattern is cataloged.

Also fix table name in LoadByOrganizationIDAndCommonThirdPartyID
(vendors -> third_parties).

Signed-off-by: Émile Ré <emile@probo.com>

pkg/coredata/third_party.go

@@ -1352,7 +1352,7 @@ SELECT
 	created_at,
 	updated_at
 FROM
-	vendors
+	third_parties
 WHERE
 	%s
 	AND organization_id = @organization_id