Update CodeQL workflow to v4 and replace deprecated LGTM badges (#1079)

* Add CodeQL workflow and replace deprecated LGTM badges

.github/workflows/codeql.yml

@@ -0,0 +1,39 @@
+name: "CodeQL"
+
+on:
+  push:
+    branches: [ "main", "master" ]
+  pull_request:
+    branches: [ "main", "master" ]
+
+  schedule:
+    - cron: '30 1 * * 0'
+
+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 repository
+      uses: actions/checkout@v4
+
+    - name: Initialize CodeQL
+      uses: github/codeql-action/init@v4
+      with:
+        languages: ${{ matrix.language }}
+
+    - name: Autobuild
+      uses: github/codeql-action/autobuild@v4
+
+    - name: Perform CodeQL Analysis
+      uses: github/codeql-action/analyze@v4

README.md

@@ -5,8 +5,9 @@
 [![npm](https://img.shields.io/npm/v/svgedit.svg)](https://www.npmjs.com/package/svgedit)
 [![Actions Status](https://github.com/SVG-Edit/svgedit/workflows/Node%20CI/badge.svg)](https://github.com/SVG-Edit/svgedit/actions)
 [![Known Vulnerabilities](https://snyk.io/test/github/SVG-Edit/svgedit/badge.svg)](https://snyk.io/test/github/SVG-Edit/svgedit)
-[![Total Alerts](https://img.shields.io/lgtm/alerts/g/SVG-Edit/svgedit.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/SVG-Edit/svgedit/alerts)
-[![Code Quality: Javascript](https://img.shields.io/lgtm/grade/javascript/g/SVG-Edit/svgedit.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/SVG-Edit/svgedit/context:javascript)
+[![CodeQL](https://github.com/SVG-Edit/svgedit/actions/workflows/codeql.yml/badge.svg)](https://github.com/SVG-Edit/svgedit/actions/workflows/codeql.yml)
+
+
 
 **SVGEdit** is a fast, web-based, JavaScript-driven SVG drawing editor that
 works in any modern browser. **SVGEdit** is based on a powerful SVG canvas **@svgedit/svgcanvas**