Add native nix-snapshotter support to rootless k3s

[elpdt852]

Meta issue for tracking work to land native support for nix-snapshotter in rootless k3s

• [x] Cherry-pick needed commits to containerd release/1.7: https://github.com/containerd/containerd/issues/9826
• [x] Wait for containerd 1.7.x release
• [ ] Wait for k3s to adopt containerd 1.7.x release: https://github.com/k3s-io/containerd
• [ ] Merge PR to add nix-snapshotter PR to k3s: https://github.com/k3s-io/k3s/pull/9319
• [x] Backport k3s PR to a k3s release cycle: https://github.com/k3s-io/k3s/pull/9309
• [x] Backport k3s PR to a k3s release cycle: https://github.com/k3s-io/k3s/pull/9308

Nice to have

• [x] Backport k3s PR to a k3s release cycle: https://github.com/k3s-io/k3s/pull/9512
• [ ] Fix: https://github.com/containerd/nerdctl/issues/2831