house-keeping: Enable Code Query Language (CodeQL) scanning

Code quality scanning (for JavaScript, JSON, HTML) for pushes and PRs
to master.

A repo scan takes roughly 4 minutes.

Signed-off-by: Paul Donald <newtwen@gmail.com>

.github/codeql/codeql-config.yml

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+name: "CodeQL config"
+
+# Paths example; these are completely different from the same keywords when used for on.<push|pull_request>.paths in a workflow
+# Restrict code scanning to files in specific directories by adding a paths array
+paths:
+  - '**/*.js'
+  - '**/*.json'
+  - '**/*.htm*'
+# # Exclude files in specific directories from analysis by adding a paths-ignore array
+# paths-ignore: 
+#   - src/node_modules
+#   - '**/*.test.js'
+
+# # Scanner packs example
+# packs:
+#   # Use these packs for JavaScript and TypeScript analysis
+#   javascript:
+#     - scope/js-pack1
+#     - scope/js-pack2
+
+
+# # Query filters example
+# query-filters:
+# - exclude:
+#     problem.severity:
+#       - warning
+#       - recommendation
+
+# # Query filters example 2
+# query-filters:
+#   - exclude:
+#       id: js/redundant-assignment
+#   - exclude:
+#       id: js/useless-assignment-to-local

.github/workflows/codeql.yml

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+name: "LuCI repo CodeQL Analysis"
+
+on:
+  push:
+    branches: [ "master" ]
+    paths:
+      # These help avoid unnecessary scans by limiting to those pushes (with commits) that contain JavaScript
+      - '**/*.js'
+      - '**/*.json'
+      - '**/*.htm*'
+  pull_request:
+    branches: [ "master" ]
+    # These paths(-ignore) set conditions that determine whether the actions in the workflow will run on a pull request.
+    # They do not determine what files will be analyzed when the actions *are* run.
+    paths:
+      # These help avoid unnecessary scans by limiting to those PRs (with commits) that contain JavaScript
+      - '**/*.js'
+      - '**/*.json'
+      - '**/*.htm*'
+    # paths-ignore:
+    #   - '**/*.md'
+    #   - '**/*.txt'
+  # Analyze also on a regular schedule
+  # schedule:
+    # Every Friday (5) at 13:33
+    # - cron: '33 13 * * 5'
+
+jobs:
+  analyze:
+    name: Analyze JavaScript and JSON
+    # Runner size impacts CodeQL analysis time. To learn more, please see:
+    #   - https://gh.io/recommended-hardware-resources-for-running-codeql
+    #   - https://gh.io/supported-runners-and-hardware-resources
+    #   - https://gh.io/using-larger-runners
+    # Consider using larger runners for possible analysis time improvements.
+    runs-on: ${{ 'ubuntu-latest' }}
+    timeout-minutes: ${{ 360 }}
+    permissions:
+      # required for all workflows
+      security-events: write
+
+      # only required for workflows in private repositories
+      # actions: read
+      # contents: read
+
+    strategy:
+      fail-fast: false
+      matrix:
+        language: [ 'javascript-typescript' ]
+        # CodeQL supports [ 'c-cpp', 'csharp', 'go', 'java-kotlin', 'javascript-typescript', 'python', 'ruby', 'swift' ]
+        # Use only 'java-kotlin' to analyze code written in Java, Kotlin or both
+        # Use only 'javascript-typescript' to analyze code written in JavaScript, TypeScript or both
+        # Learn more about CodeQL language support at https://aka.ms/codeql-docs/language-support
+
+    steps:
+    - name: Check out repository
+      uses: actions/checkout@v4
+
+    # Initializes the CodeQL tools for scanning.
+    - name: Initialize CodeQL
+      uses: github/codeql-action/init@v3
+      with:
+        config-file: ./.github/codeql/codeql-config.yml
+        languages: ${{ matrix.language }}
+        # If you wish to specify custom queries, you can do so here or in a config file.
+        # By default, queries listed here will override any specified in a config file.
+        # Prefix the list here with "+" to use these queries and those in the config file.
+
+        # For more details on CodeQL's query packs, refer to: https://docs.github.com/en/code-security/code-scanning/automatically-scanning-your-code-for-vulnerabilities-and-errors/configuring-code-scanning#using-queries-in-ql-packs
+        # queries: security-extended,security-and-quality
+        # Config example:
+        # config: |
+        #   disable-default-queries: true
+        #   queries:
+        #     - uses: security-extended
+        #   query-filters:
+        #     - exclude:
+        #       tags: /cwe-020/
+
+
+    # Autobuild attempts to build any compiled languages (C/C++, C#, Go, Java, or Swift).
+    # If this step fails, then you should remove it and run the build manually (see below)
+    # For LuCI we likely do not need to build. JS just runs. Very little C in the repo.
+    # - name: Autobuild
+    #   uses: github/codeql-action/autobuild@v3
+
+    # ℹ️ Command-line programs to run using the OS shell.
+    # 📚 See https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#jobsjob_idstepsrun
+
+    #   If the Autobuild fails above, remove it and uncomment the following three lines.
+    #   modify them (or add more) to build your code. Please refer to the EXAMPLE below for guidance.
+
+    # - run: |
+    #     echo "Run, Build Application using script"
+    #     ./location_of_script_within_repo/buildscript.sh
+
+    - name: Perform CodeQL Analysis
+      uses: github/codeql-action/analyze@v3
+      with:
+        category: "/language:${{matrix.language}}"