Update and fix all links pointing to readthedocs

[merelcht]

Motivation and Context

I noticed the links in the starters are all still pointing to kedro.readthedocs and some of them are not even redirected properly. I fixed them all in this PR.

How has this been tested?

Checklist

• [ ] Opened this PR as a 'Draft Pull Request' if it is work-in-progress
• [ ] Assigned myself to the PR
• [ ] Added tests to cover my changes