[clang] Reapply "[Clang] Implement P3034R1 Module Declarations Shouldn’t be Macros" (PR #102135)

[via cfe-commits]

cor3ntin wrote:

This PR is starting to get quite large. Can [Modules Dependency Discover](https://github.com/llvm/llvm-project/pull/102135/commits/581160a121fca5796bff2392d9228207d37e6f16) be split in a separate PR?

https://github.com/llvm/llvm-project/pull/102135