[clang-tools-extra] Add refactoring tool to convert between ternary (?:) expressions and equivalent if/else statements (PR #166822)

[Baranov Victor via cfe-commits]

vbvictor wrote:

I gave modernize category as an example that transformations can be done in clang-tidy. This to me is the readability category.

To proceed further we need tests and docs for the check, see how other checks were implemented. (you can check git log and find related PRs)

https://github.com/llvm/llvm-project/pull/166822