README and license cleanup

- Remove Code Climate badges
- Fix dead documentation links (docs.kitchen-ci.org and old
  downloads.chef.io/docs.chef.io paths are gone; ChefDK is superseded by
  Chef Workstation), and repoint chef/* GitHub links at test-kitchen/*
- Replace the "enter-github-user" placeholder links left over from the
  gem template
- Point LICENSE links at the branch and filename that actually exist
- Normalize the gemspec license to the SPDX identifier "Apache-2.0" so it
  matches the shipped LICENSE file

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Signed-off-by: Tim Smith <tsmith84@proton.me>

Author: tas50

README.md

@@ -56,7 +56,7 @@ Created and maintained by [Andrew Leonard](http://andyleonard.com)
 ([andy@hurricane-ridge.com](mailto:andy@hurricane-ridge.com)).
 
 The initial release drew heavily on the
-[kitchen-ec2](https://github.com/chef/kitchen-ec2/) gem for both
+[kitchen-ec2](https://github.com/test-kitchen/kitchen-ec2) gem for both
 inspiration and implementation details. Any bugs, however, are solely
 the author's own doing.