Draft: kernels: add depthcharge-tools subpackage

It is currently set as a dependency in alpine, but it is intended to be an optional dependency, so I'm going to remove it from there

https://gitlab.alpinelinux.org/alpine/aports/-/blob/94f624fe649edd6d5a1dd7e069e985753ca16182/testing/depthcharge-tools/APKBUILD#L13

I suggest depending on it in subpackages