Migrate Key Vault client generation to TypeSpec

[chlowell]

This issue tracks migrating Key Vault client generation from OpenAPI to TypeSpec:

• [ ] administration

[!Important] Certificates, Keys and Secrets do not have generated code as of today, so they are out of scope for this migration.

This is the high-level process for each library:

• add language-specific configuration to the library's tspconfig.yaml in the azure-rest-api-specs repo. See these PRs:
  • https://github.com/Azure/azure-rest-api-specs/pull/30239
  • https://github.com/Azure/azure-rest-api-specs/pull/28708
  • https://github.com/Azure/azure-rest-api-specs/pull/29248
  • https://github.com/Azure/azure-rest-api-specs/pull/29249
• check tsp-client setup for SDK repo (docs)
• add tsp-location.yaml for the library (docs, example)
• generate code with tsp-client
• add customization to client.tsp (example)

[jsquire]

Please be aware that .NET will not be performing a full generation from TypeSpec. We will migrate the clients that are currently generated but will not be investing in generating those clients that are hand-written at this time. Generated clients will continue to be internal; we will not be generating the public API.

//cc: @chlowell, @JonathanCrd

[JonathanCrd]

@chlowell my understanding is that each of us will work with a Client.tsp to figure out what customization we need, and then once we all have our customizations we're going to merge them together (and simplify them). Is that correct? Or do we have a common Client.tsp already?

[chlowell]

That's my understanding as well. The TSP PRs don't include a client.tsp and may not--it's reasonable to add it in a separate PR--so feel free to create one for your local development in the meantime.