[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/application.go

@@ -26,7 +26,7 @@ import (
 )
 
 type applicationDB struct {
-	db    *DB
+	db    *bun.DB
 	state *state.State
 }