added check URLs action

Author: stuhli

.github/workflows/check_urls.yml

@@ -0,0 +1,14 @@
+name: Check URLs
+on: [pull_request, push]
+
+jobs:
+  check-urls:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4
+    - uses: urlstechie/urlchecker-action@master
+      with:
+        file_types: .md
+        exclude_files: 'dfirtrack_main/tests/'