feat: add ctr extension

[tomaszjonak]

This PR provides containerd ctr binary in a form of a stanadlone talos extension. Counterpart to siderolabs/pkgs#1186.

cc @redhatrises.

Closes #622

[smira]

Same questions as in siderolabs/pkgs#1186, and also pkgs path is better than downloading binary release.

[redhatrises]

@smira with siderolabs/pkgs#1186 merged. Do we need to make changes to this PR?

[smira]

@redhatrises I don't know, if you want ctr as a system extension, you need to make a PR to extensions - either new one, or updating this one? I don't know if you and @tomaszjonak are working together?

[tomaszjonak]

@smira yes, we are working together. I will update this PR as needed.

and also pkgs path is better than downloading binary release

I'm not versed enough in talos build system. Could you expand on how this should be done. I.e is there another extension that utilizes such flow.

[smira]

I don't know something that matches 100%, but e.g. https://raw.githubusercontent.com/smira/extensions/e974d6e1fcd28b064c37c4c2bec6c3cc8159f6c2/firmware/qlogic-firmware/pkg.yaml

So you take containerd container image built by pkgs and just extract ctr from it, and put it under /rootfs/usr/bin. Should be relatively simple.

You also might need to bump PKGS to be the latest (use git describe --tags in pkgs repo) in .kres.yaml and make rekres.