[feature/performance] sqlite pragma optimize on close (#2596)

* wrap database drivers in order to handle error processing, hooks, etc

* remove dead code

* add code comment, remove unused blank imports

internal/db/bundb/instance.go

@@ -34,7 +34,7 @@ import (
 )
 
 type instanceDB struct {
-	db    *DB
+	db    *bun.DB
 	state *state.State
 }