Add a link checker github action

[llhuii]

What would you like to be added/modified: Add a link checker github action.

Why is this needed: Since a new pull request may make mistake in broken links, a link checker can be used to automatically detect this kind problem.

[llhuii]

I have found some solutions in k8s community:

1. https://github.com/kubernetes/community/issues/359
2. https://github.com/kubernetes/website/blob/main/scripts/linkchecker.py

[llhuii]

Note we only need to check the sedna repo links.

[khalid-huang]

/assign