feat: add codeql workflow

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

.github/workflows/codeql.yml

@@ -0,0 +1,39 @@
+# SPDX-FileCopyrightText: 2021 The HedgeDoc developers (see AUTHORS file)
+#
+# SPDX-License-Identifier: AGPL-3.0-only
+
+name: "CodeQL"
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+  schedule:
+    - cron: "54 23 * * 2"
+
+jobs:
+  analyze:
+    name: Analyze
+    runs-on: ubuntu-latest
+    permissions:
+      actions: read
+      contents: read
+      security-events: write
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v2
+        with:
+          languages: TypeScript
+          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:TypeScript"