nice to have: Support for patches in git submodules

[lamikr]

Current patch mechanism only support patches in main-projects which is one reason why aotriton project has been flattened to single repo. (aotriton)

Implementation idea based on to aotriton which has 3 git submodules located in directories

third_party/triton/
third_party/pypind11/
third_party/incbin/

Under the projects main patch dir, there could be similar sub-directory structure than in main project to easy for marking the directories where to do the patch apply. For example in the aotriton project the patches directory structure could be

patches/rocm-6.1.1/aotriton/001-aotriton-main-project_change1.patch
patches/rocm-6.1.1/aotriton/third_party/triton/change1.patch
patches/rocm-6.1.1/aotriton/third_party/triton/change2.patch
patches/rocm-6.1.1/aotriton/third_party/pypind11/change1.patch