[llvm] [DWARFLinker][DWARFLinkerParallel][NFC] Refactor DWARFLinker&DWARFLinkerParallel to have a common library. Part 1. (PR #75925)

[Felipe de Azevedo Piovezan via llvm-commits]

https://github.com/felipepiovezan commented:

Since we now have a base class for linker implementations, I looked at its documentation from the perspective of "what do I need to do in order to implement a new linker".

Left some writing suggestions! Hopefully others will have a look as well

https://github.com/llvm/llvm-project/pull/75925