[bug] Docs: Document migration ways for bunch of tools helpers

### Describe the bug

It is pretty hard to search for commits / switch between docs / google in Internet about some tools helpers. It would be better to be in conan v2 migration guide (which, I think, should be included in conan v2 docs).

The missing helpers are:
- VisualStudioBuildEnvironment - how is better to switch it? (found some potential relevant info here: https://github.com/conan-io/conan/issues/12188#issuecomment-1326758649)
- no_op() env helper - provide an example how to rewrite code fragment
- tools.which() - replace to shutil.which()
- tools.remove_files_by_mask() - tools.files.rm()

I suspect there are more examples which should be documented in migration guide too to reduce the frustration of searching...

### How to reproduce it

_No response_