Deprecate previous sdk generation tooling

With `tsp-client`, documentation and scripts for additional TypeSpec tooling is no longer necessary. To make sure our users don't get confused, we should remove these tooling.

- https://github.com/Azure/azure-sdk-tools/blob/main/doc/common/TypeSpec-Project-Scripts.md
- https://github.com/Azure/azure-sdk-tools/blob/main/eng/common/scripts/TypeSpec-Project-Generate.ps1
- https://github.com/Azure/azure-sdk-tools/blob/main/eng/common/scripts/TypeSpec-Project-Sync.ps1
- https://github.com/Azure/azure-sdk-tools/blob/main/eng/common/scripts/TypeSpec-Project-Process.ps1

CADL tooling?
#9427

[Spec repo](https://github.com/search?q=repo%3AAzure%2Fazure-rest-api-specs+typespec-project&type=code) references:
- Documentation that needs to be updated to use tsp-client
- Also, issue filed by a user: https://github.com/Azure/azure-rest-api-specs/issues/30544

Language repos references:
- .[NET](https://github.com/search?q=repo%3AAzure%2Fazure-sdk-for-net%20typespec-project&type=code):
- DPG documentation (seems out of date?)
- #9422
- [Java](https://github.com/search?q=repo%3AAzure%2Fazure-sdk-for-java%20typespec-project&type=code):
- #9421
- [Python](https://github.com/search?q=repo%3AAzure%2Fazure-sdk-for-python%20typespec-project&type=code):
- [TypeSpec refresh SDK](https://github.com/Azure/azure-sdk-for-python/blob/main/scripts/typespec_refresh_sdk/main.py)
- [JS](https://github.com/search?q=repo%3AAzure%2Fazure-sdk-for-js%20typespec-project&type=code)
- Documentation
- #9420
- https://github.com/Azure/azure-sdk-for-js/pull/33296
- [Go](https://github.com/search?q=repo%3AAzure%2Fazure-sdk-for-go%20typespec-project&type=code)
- https://github.com/Azure/azure-sdk-for-go/issues/23797