Decouple log extraction from transformer delegation

- limit missing headers results set to 100 so that extraction doesn't
  excessively block delegation
- wrap checked headers functions in repository struct
- move storage repository to factory, to correspond with event
  repository path
- remove unused files
- reformat sql
- remove line breaks in imports

libraries/shared/constants/checked_headers.go

@@ -21,5 +21,5 @@ type TransformerExecution bool
 const (
 	HeaderRecheck    TransformerExecution = true
 	HeaderMissing    TransformerExecution = false
-	RecheckHeaderCap                      = "4"
+	RecheckHeaderCap                      = int64(5)
 )