Add "Supported Distros" column to Features table (and consider adding to spec)

I've encountered situations where I want to add a Feature to a devcontainer configuration, only to discover later that it supports only certain distros or package managers. This typically becomes apparent only at build time, leading to wasted effort.

To improve the experience, I'd like to suggest adding a "Supported Distros" column to the Features table at https://containers.dev/features. Displaying this information up front (rather than having it buried in project READMEs) would make it easier to determine whether a Feature can be used with a specific base image or distro, saving time and reducing confusion.

Since the spec already acknowledges this limitation in the [docs](https://containers.dev/implementors/features/):

> Note: While Features may be installed on top of any base image, the implementation of a Feature might restrict it to a subset of possible base images. For example, some Features may be authored to work with a certain Linux distro (e.g. debian-based images that use the apt package manager).

It might be worth adding a `supportedDistros` property to the `devcontainer-feature.json` spec itself. This would improve discoverability, allow the documentation to be auto-generated and ensure distro compatibility is consistently documented across all Features.

Thanks for considering this enhancement!