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

pkg/core/receipts.go

@@ -21,7 +21,7 @@ type Receipt struct {
 	ContractAddress   string `db:"contract_address"`
 	CumulativeGasUsed uint64 `db:"cumulative_gas_used"`
 	GasUsed           uint64 `db:"gas_used"`
-	Logs              []Log
+	Logs              []FullSyncLog
 	StateRoot         string `db:"state_root"`
 	Status            int
 	TxHash            string `db:"tx_hash"`