staging: extract CRI streaming modules with client-go compatibility

Extract streaming code into dedicated staging modules while keeping stable
compatibility APIs for external client-go consumers.

This commit:
- adds `k8s.io/cri-streaming` for CRI exec/attach/portforward server code
- adds `k8s.io/streaming` as the canonical home for shared transport
  primitives (`httpstream`, `spdy`, `wsstream`, runtime helpers)
- switches in-tree transport consumers to `k8s.io/streaming`
- removes in-tree kubelet CRI streaming package
- preserves NO_PROXY/no_proxy CIDR handling in extracted SPDY proxier logic
- adds deprecated `k8s.io/apimachinery/pkg/util/httpstream` compatibility
  wrappers (`httpstream`, `spdy`, `wsstream`) backed by `k8s.io/streaming`
- restores exported client-go SPDY/portforward API signatures to
  apimachinery `httpstream` types for downstream compatibility
- adds streaming-native client-go adapters/constructors so in-tree callers
  can use `k8s.io/streaming` without changing external compatibility APIs
- deduplicates SPDY-over-websocket dial negotiation shared by compat and
  streaming tunneling dialers
- logs dropped unknown stream types in `RemoveStreams` adapter fallbacks to
  improve compatibility-path debuggability
- adds integration coverage for the streaming-upgrader-to-client-go-compat
  adapter path against a real cri-streaming exec endpoint
- clarifies kubectl streaming import aliasing to avoid `httpstream` package
  ambiguity
- updates tests, import restrictions, publishing metadata, and vendor/module
  metadata for the new staging modules

Signed-off-by: Davanum Srinivas <davanum@gmail.com>

Kubernetes-commit: 1ee1ff97fb7f9755a44d29bee0c80d2ccbed68dc