Add CodeQL workflow for GitHub code scanning (#2948)

Co-authored-by: LGTM Migrator <[email protected]>

.github/codeql.yml

@@ -0,0 +1,7 @@
+paths-ignore:
+  - sites/x6-sites/static
+query-filters:
+  - exclude:
+      id: js/use-before-declaration
+  - exclude:
+      id: js/polynomial-redos

.github/workflows/codeql.yml

@@ -0,0 +1,42 @@
+name: "CodeQL"
+
+on:
+  push:
+    branches: [ "master", "bot", "gh-pages", "v1" ]
+  pull_request:
+    branches: [ "master" ]
+  schedule:
+    - cron: "41 2 * * 1"
+
+jobs:
+  analyze:
+    name: Analyze
+    runs-on: ubuntu-latest
+    permissions:
+      actions: read
+      contents: read
+      security-events: write
+
+    strategy:
+      fail-fast: false
+      matrix:
+        language: [ javascript ]
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v2
+        with:
+          languages: ${{ matrix.language }}
+          config-file: ./.github/codeql.yml
+          queries: +security-and-quality
+
+      - name: Autobuild
+        uses: github/codeql-action/autobuild@v2
+
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@v2
+        with:
+          category: "/language:${{ matrix.language }}"