Have check_compliance.py Kconfig whitelist live in zephyr repo

[galak]

Its a bit of a pain for developers to have to submit a fix the ci-tools/check_compliance.py repo/file for a Kconfig whitelist update. Can we move the whitelist to a file and keep it in the zephyr repo?

[galak]

@Sizurka, @sigvartmh fyi.

[ulfalizer]

The reason I didn't do that right away is that I think the right solution is to move ci-tools back into the main Zephyr repo instead. There will be other whitelists later on too, and it's annoying if you have to have a custom whitelist file for each, that supports comments, etc., and with the extra code that comes with that.

It feels like working around that ci-tools would be better to have as scripts/ci in the Zephyr repo, where it used to be.

I was kinda hoping that someone would take the initiative and move it back, but I could make a PR for it later otherwise.