Moved generic and broadly useful helper functions upstream into feedkit

internal/sinks/postgres/map_test.go

@@ -238,7 +238,7 @@ func assertAllWritesIncludeAllColumns(t *testing.T, writes []fksinks.PostgresWri
 }
 
 func tableColumnCounts() map[string]int {
-	s := weatherPostgresSchema()
+	s := PostgresSchema()
 	m := make(map[string]int, len(s.Tables))
 	for _, tbl := range s.Tables {
 		m[tbl.Name] = len(tbl.Columns)