chore: add recommended extensions and settings (#200)

Author: nirinchev

.vscode/extensions.json

@@ -0,0 +1,9 @@
+{
+  // See https://go.microsoft.com/fwlink/?LinkId=827846 to learn about workspace recommendations.
+  // Extension identifier format: ${publisher}.${name}. Example: vscode.csharp
+
+  // List of extensions which should be recommended for users of this workspace.
+  "recommendations": ["firsttris.vscode-jest-runner", "orta.vscode-jest"],
+  // List of extensions recommended by VS Code that should not be recommended for users of this workspace.
+  "unwantedRecommendations": []
+}

.vscode/settings.json

@@ -0,0 +1,11 @@
+{
+  "jestrunner.jestCommand": "npm test --",
+  "jestrunner.debugOptions": {
+    "runtimeExecutable": "node",
+    "runtimeArgs": [
+      "--experimental-vm-modules",
+      "node_modules/jest/bin/jest.js",
+      "--coverage"
+    ]
+  }
+}