Add matching based on platform.features and platform.compatibilities

[mfranczy]

That is a simple prototype to show how we could improve image selection in containerd.
The code of this prototype should be improved and maybe platforms in a few places refactored, however, it solves the problem and shows the general idea which is:

• use platform.features for CPU features
• introduce platform.compatibilities which is a map that allows to provide matching labels.

Additionally, I introduced a new config file /etc/containerd/platform-config.toml where people can provide information to containerd services about nodes cpu features and compatibility data.

Example of the new config file:

features = ["avx512"]

[compatibilities]
  "oci.kernel.modules.kvm" = "true"

[mfranczy]

I am sorry, that suppose to be only for oci-playground repo. Not the core containerd repo.