Add CodeQL workflow for GitHub code scanning

.github/codeql.yml

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+paths:
+  - src/tools

.github/workflows/codeql.yml

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+name: "CodeQL"
+
+on:
+  push:
+    branches: [ "7.0", "3.13", "3.14", "3.15", "3.16" ]
+  pull_request:
+    branches: [ "7.0" ]
+  schedule:
+    - cron: "2 10 * * 0"
+
+jobs:
+  analyze:
+    name: Analyze
+    runs-on: ubuntu-latest
+    permissions:
+      actions: read
+      contents: read
+      security-events: write
+
+    strategy:
+      fail-fast: false
+      matrix:
+        language: [ python, cpp ]
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Install Packages (cpp)
+        if: ${{ matrix.language == 'cpp' }}
+        run: |
+          sudo apt-get update
+          sudo apt-get install --yes libreadline-dev
+
+      - 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
+        if: ${{ matrix.language == 'python' }}
+
+      - name: Build cpp
+        if: ${{ matrix.language == 'cpp' }}
+        run: |
+          g++ --version
+          make --version
+          perl --version
+          make -sj2 || echo '*** Build failed, ignored for lgtm ***'
+
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@v2
+        with:
+          category: "/language:${{ matrix.language }}"