Remove the Katacoda training

[bobbyiliev]

Removing the Katacoda training as it is no longer available

[what-the-diff]

PR Summary

• Removal of the "Interactive Training" Section from README.md
  The PR includes deletion of the whole interactive training section from the README file. This section previously provided links to training resources and the Katacoda repository.

• Removal of "Interactive Training" Link from Navigation Bar
  The "Interactive Training" link that was previously located in the navigation bar of the main page (index.html) has also been removed.

• Elimination of the Entire "Training Section" from Index.html
  The comprehensive "Training Section" from the main page that included a descriptive header, an option to start free training, and a relevant image has now been deleted.

• Additional "Interactive Training" Link Erased
  An extra link that directed users to "Interactive Training", found towards the end of the main page, has also been gotten rid of.