[llvm] [docs][CMake] Add CMakePreset, improve VS documentation (PR #84760)

[James Henderson via llvm-commits]

jh7370 wrote:

I personally don't get on with the built-in CMake support within Visual Studio. I've got no issue with documenting how to use it or adding "sensible" defaults (I have a suspicion that there is no specific "sensible" default for any given user), but I would prefer us avoiding stating that one way is preferred above another way, especially without an RFC discussion to formalise this stance: let each user decide for themselves which method they'd prefer to use.

https://github.com/llvm/llvm-project/pull/84760