[clang] [clang-tools-extra] [PAC][clang] Define `PointerAuthQualifier` and `PointerAuthenticationMode` (PR #84384)

[Daniil Kovalev via cfe-commits]

kovdan01 wrote:

> have you tried an approach where this information is stored in `ExtQuals` instead?

Not yet, thanks for suggestion. I'll try and let you know about results

https://github.com/llvm/llvm-project/pull/84384