Write instructions for API producers to setup internal/private repos for advertising APIs to Kiota search

[baywet]

• Create the repo
• Add topic to the repo
• Create the OpenAPI description (possibly from CSDL)
• Add the Apis.json/yaml file to include the OpenAPI in the Kiota search index.
• Assign customers access to the repo to enable them to discover the API
• Point customers to docs to describe the self-serve process

original issue microsoft/kiota#1984 will assign to @RabebOthmani once she's part of the organization

[baywet]

@sebastienlevert we already have a public documentation page that covers that topic here for internal audiences, we probably need something that refers to that, and lets them know how to provision the repo/handle the security/etc...
I suggest we close that issue, thoughts?

[sebastienlevert]

I think we need to keep it for the rest of the internal setups. It's a good reminder that I need to get to this...