[Alternative to 148] go.mod: github.com/containerd/containerd/v2 v2.0.0-rc.0

[AkihiroSuda]

Similar to PR #148, but does not bump up urfave/cli.

• cmd/ctr is kept to use urfave/cli v1, but its containerd library is bumped up from v1.6 to v1.7 due to dependencies. typeurl is bumped up from v1 to v2 as a part of them.

• cmd/ctr/v2v1glue and cmd/ctr/v1v2glue are added for using containerd v2-based encryption library from containerd v1-based CLI.

• cmd/ctr/commands/tasks was copied from https://github.com/containerd/containerd/tree/v1.7.14/cmd/ctr/commands/tasks, but metrics.go was removed due to a dependency issue: containerd v1 depends on hcsshim v0.11, while containerd v2 depends on hcsshim v0.12.

• • -

• Contains #152

[AkihiroSuda]

Looks like we can't import containerd v1 and v2 together

panic: proto: file "github.com/containerd/containerd/core/runtime/v2/runc/options/oci.proto" has a name conflict over containerd.runc.v1.ProcessDetails
    previously from: "github.com/containerd/containerd/runtime/v2/runc/options"
    currently from:  "github.com/containerd/containerd/v2/core/runtime/v2/runc/options"
See https://protobuf.dev/reference/go/faq#namespace-conflict

https://github.com/containerd/imgcrypt/actions/runs/8464452194/job/23189151410?pr=153