Add CI for checking for broken links manually, weekly and in PRs

[markcmiller86]

Resolves: #1431

Links will get checked automatically weekly at 5:17 AM on Sundays. They can also be checked manually by just running the workflow.

We need to adjust the filters used in the checker and there are a lot of broken links found (see #1632)

• Set list of Reviewers (at least one).
• Add to Project BSSw Internal.
• [ ] View the modified *.md files as rendered in GitHub.
• [ ] If changes are to the GitHub pages site under the docs/ directory, consider viewing locally with Jekyll.
• Watch for PR check failures.
• Make any final changes to the PR based on feedback and review GitHub (and Jekyll) rendered files.
• Ensure at least one reviewer signs off on the changes.
• Once reviewer has approved and PR check pass, then merge the PR.

[bartlettroscoe]

@markcmiller86, please @mention me and let me know when this is ready to review

[markcmiller86]

Apologies...I converted to DRAFT for time being.

[markcmiller86]

Have adjusted it to ignore...

• docs -- those links are often not really public...EB should fix but we can do as encountered.
• Events -- short lived and links are likely to stale over time

[markcmiller86]

Ok, this addresses all the cases in #1632.

I am pulling out of DRAFT mode. Its ready for review.

[markcmiller86]

@rinkug, @bartlettroscoe and @bernhold this is now ready for review.

The weekly CI check should result in a small list of either bonified broken links or false negatives (e.g. says its broken when its not) to try to check and then either go edit files to fix, add to ignore patterns or just ignore.

[vsoch]

I'm going to unsubscribe from notifications here - good luck @markcmiller86 !