Remove credentials and auth angular controllers

[GilbertCherrie]

Remove unused angular credentials controller and associated haml files. This controller looks like it was used on the old provider forms to handle the credentials fields (#726). Since all the provider forms are now in React we can remove this controller. Example of new React provider form:

Remove unused angular credentials controller and associated haml files. This controller looks like it was used on the old ansible provider forms to handle the auth fields (#2867). Since all the provider forms are now in React we can remove this controller. This is the new React configuration provider form:

Cleared field set focus is now also no longer needed as the functions it defines were only used by these 2 controllers and their haml files.

[miq-bot]

Checked commit GilbertCherrie@c5d0bfa with ruby 2.7.8, rubocop 1.56.3, haml-lint 0.51.0, and yamllint
0 files checked, 0 offenses detected
Everything looks fine. 🏆