[R4R] DTL response null result with 404 http status

[shidaxi]

Goals of PR

Core changes:

• handler support return http status code
• return 404 http status code when result is null

Related Issues:

• with this we can enable cache safely

[shidaxi]

Test

curl "localhost:7878/transaction/index/87?backend=l2" -i

HTTP/1.1 404 Not Found
X-Powered-By: Express
Access-Control-Allow-Origin: *
Content-Type: application/json; charset=utf-8
Content-Length: 33
ETag: W/"21-CMqNFJ1GmGJsYiAIPHNf2iBKJ9E"
Date: Fri, 22 Dec 2023 12:51:18 GMT
Connection: keep-alive
Keep-Alive: timeout=5

{"transaction":null,"batch":null}

                                                                                                                                    
curl "localhost:7878/transaction/index/86?backend=l2" -i

HTTP/1.1 200 OK
X-Powered-By: Express
Access-Control-Allow-Origin: *
Content-Type: application/json; charset=utf-8
Content-Length: 1054
ETag: W/"41e-LAO9Ef7iD5peiLs9WMbN9FjpsHw"
Date: Fri, 22 Dec 2023 12:51:24 GMT
Connection: keep-alive
Keep-Alive: timeout=5

{"transaction":{"index":86,"value":"0x0","batchIndex":null,"blockNumber":16005,"timestamp":1703089712,"queueOrigin":"sequencer","confirmed":false,"gasLimit":"0","target":"0x0000000000000000000000000000000000000000","origin":null,"data":"0xf8a8808402faf08082864294deaddeaddeaddeaddeaddeaddeaddeaddead111180b844a9059cbb00000000000000000000000000000500e87ee83a1bfa233512af25a4003836c800000000000000000000000000000000000000000000000000005af3107a400045a045f220e8638eb5f5cdb2259efbdd36533597eae1776d9fdc81d2914d59f60203a03e5202f7743b809bebbe8b8a181ae4f55a472f6b9b5de1ff695c29a102c0037e","decoded":{"sig":{"v":0,"r":"0x45f220e8638eb5f5cdb2259efbdd36533597eae1776d9fdc81d2914d59f60203","s":"0x3e5202f7743b809bebbe8b8a181ae4f55a472f6b9b5de1ff695c29a102c0037e"},"value":"0x0","gasLimit":"34370","gasPrice":"50000000","nonce":"0","target":"0xdeaddeaddeaddeaddeaddeaddeaddeaddead1111","data":"0xa9059cbb00000000000000000000000000000500e87ee83a1bfa233512af25a4003836c800000000000000000000000000000000000000000000000000005af3107a4000"},"queueIndex":null},"batch":null}