Add CodeQL Action (#4315)

Make the server-side code safer by using CodeQL checking.

Author: XhmikosR

.github/workflows/codeql.yml

@@ -0,0 +1,33 @@
+name: "CodeQL"
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+  schedule:
+    - cron: "0 0 * * 0"
+  workflow_dispatch:
+
+jobs:
+  analyze:
+    name: Analyze
+    runs-on: ubuntu-latest
+    permissions:
+      actions: read
+      contents: read
+      security-events: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v1
+        with:
+          languages: "javascript"
+
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@v1