[C#] docs: Created C# README equivalent to JS README file #1057

[Carter425]

#minor
Creating a C# README doc equivalent to the JS README doc, but with updated C# links and language. IMPORTANT - The example/basic code under Migration section and under AI Prompt manager still needs to be changed to C# from JS. I would need Kavin or Alex to ensure this is done correctly. Alternatively, I can take this code out and just have people refer to the Migration Guide and AI Setup Guide links.

Attestation Checklist

• My code follows the style guidelines of this project

• I have checked for/fixed spelling, linting, and other errors

• I have commented my code for clarity

• I have made corresponding changes to the documentation (we use TypeDoc to document our code)

• My changes generate no new warnings

• I have added tests that validates my changes, and provides sufficient test coverage. I have tested with:

  • Local testing
  • E2E testing in Teams

• New and existing unit tests pass locally with my changes

Additional information

Feel free to add other relevant information below

[Carter425]

Hi @corinagum, @singhk97, and @aacebo,

I made the equivalent README file for C# as JS has. The wording and links are updated. Importantly, as I noted above, the basic code for Migration and Prompt Manager are still in JS. I would need help here or I can just refer to the C# migration and AI Setup Guides.

[aacebo]

see comment about C# readme contents