fix broken URLs and automate broken URL checks #70

This commit:
- Fixes broken URLs using archive.org or other references.
- Replaces tenforums.com URLs with better documentation as they tend to return HTTP status code 403 to tests and also are low quality source.
- Changes all insecure http sources to https alternatives
- Adds integration tests to check for broken URLs
  - There's logic implemented for having a delay inbetween when sending requests to same domains, however it's not used as the sources can respond to totally parallelized requests.
- Run test pipeline weekly to get notified about broken URls without commits

.github/workflows/security-checks.yaml

@@ -5,7 +5,7 @@ on:
   pull_request:
     paths: [ '/package.json', '/package-lock.json' ] # Allow PRs to be green if they do not introduce dependency change
   schedule:
-    - cron: '0 0 * * 0'
+    - cron: '0 0 * * 0' # at 00:00 on every Sunday
 
 jobs:
   npm-audit: