Add hook to lint CODEOWNERS files

[vyasr]

The purpose of this hook is to ensure consistent review strategies across RAPIDS so that different projects make the most effective use of their teams for reviews. Here are some standard things we could enforce.

CI codeowners:

• /.github/
• /ci/

Packaging codeowners:

• /conda/
• dependencies.yaml
• /build.sh
• pyproject.toml
• /.pre-commit-config.yaml
• /.devcontainer/

C++ codeowners:

• cpp/

Python codeowners:

• python/
• notebooks/ # In repos this exists

CMake codeowners:
Note that order is important and these entries should come below the C++/Python entries because CODEOWNERS is order-dependent and we probably don't want to make Python or C++ devs review these files. We may need to first explicitly assign the appropriate subsets of these files to the corresponding groups before we can assign them here so that we don't add in the wrong groups.

• CMakeLists.txt
• **/cmake/
• *.cmake

[jameslamb]

+1, I support these choices of defaults and have nothing to add.

[KyleFromNVIDIA]

I've modified #60 to enforce selective ordering of these files.