**Description**
This PR adjusts the external providers documentation to align with the
new providers format. Splits up sections into the existing external
providers and how to create them as well.
<img width="1049" height="478" alt="Screenshot 2025-07-31 at 9 48 26 AM"
src="https://github.com/user-attachments/assets/f13599cb-2fd1-4e57-8ca9-27b067264e33"
/>
Open to feedback and adjusting titles