feat(QA): add test cases for websteps vs webconnectivity (#583)

This pull request introduces a set of Node.js scripts for performing A/B comparison of websteps and webconnectivity as described in https://github.com/ooni/probe/issues/1805. Rather than using Jafar, I ended up using `miniooni`'s `--censor` command line flag introduced in [v3.12.0-alpha.1](https://github.com/ooni/probe-cli/releases/tag/v3.12.0-alpha.1). The main reason for doing so is that it's simpler to run tests without requiring root access and Linux _and_ Docker (e.g., I did not develop part of this diff using Linux). Additionally, I choose to use Node.js rather than extending the existing Python framework for QA, because I found Node.js easier when working with JSON data.

.eslintrc.json

@@ -0,0 +1,13 @@
+{
+    "env": {
+        "node": true,
+        "es2021": true
+    },
+    "extends": "eslint:recommended",
+    "parserOptions": {
+        "ecmaVersion": 13,
+        "sourceType": "module"
+    },
+    "rules": {
+    }
+}