Remove dependency of .net generator from tsp converter

[pshao25]

Fix #4995

What still left is:

1. Multi path cases depend on TypeSpec design: "arm-apimanagement", "arm-compute", "arm-machinelearningservices"
2. Expanded cases depend on TypeSpec design: "arm-dns"
3. Deal with directives: an example is arm-storage.

[tadelesh]

why we still want to keep resources.json, it is kind of a middle output from .net codegen. since we have the resource detection logic, then we could compose the typespec resource model directly.

[pshao25]

why we still want to keep resources.json, it is kind of a middle output from .net codegen. since we have the resource detection logic, then we could compose the typespec resource model directly.

We can definitely delete it, and it is actual my next step. In this PR, I don't want to do take this step too big, therefore to keep this file so that we could see the diff clearly.