[llvm] [llvm-advisor] Add tool foundation (PR #207625)

[Miguel Cárdenas via llvm-commits]

miguelcsx wrote:

@tobias-stadler @kevinsala @jdoerfert  I just end up all the splitting, I'll start with this PR, once merged all the following are ready on the fork github.com/miguelcsx/llvm-project.

We can start by this one! 👍 

https://github.com/llvm/llvm-project/pull/207625