Add instructions to setup and run testnet L2 and Nitro deployments (#26)

Part of [Create a public laconicd testnet](https://www.notion.so/Create-a-public-laconicd-testnet-896a11bdd8094eff8f1b49c0be0ca3b8)

Co-authored-by: Shreerang Kale <shreerangkale@gmail.com>
Co-authored-by: Neeraj <neeraj.rtly@gmail.com>
Reviewed-on: #26
Co-authored-by: Prathamesh Musale <prathamesh.musale0@gmail.com>
Co-committed-by: Prathamesh Musale <prathamesh.musale0@gmail.com>

scripts/package.json

@@ -22,7 +22,8 @@
   },
   "scripts": {
     "build": "tsc",
-    "map-subscribers-to-participants": "node dist/map-subscribers-to-participants.js"
+    "map-subscribers-to-participants": "node dist/map-subscribers-to-participants.js",
+    "participants-with-filtered-validators": "node dist/participants-with-filtered-validators.js"
   },
   "packageManager": "yarn@1.22.19+sha1.4ba7fc5c6e704fce2066ecbfb0b0d8976fe62447"
 }