containerd integration using deprecated "cri" binary

[cpuguy83]

Describe the bug

For containerd we are fetching the deprecated standalone cri-containerd binary.
CRI is now compiled into containerd directly, this should be used instead.

Additional context

aks-engine/parts/k8s/cloud-init/artifacts/cse_install.sh

Lines 173 to 178 in f8f373d

	downloadContainerd() {
	CONTAINERD_DOWNLOAD_URL="${CONTAINERD_DOWNLOAD_URL_BASE}cri-containerd-${CONTAINERD_VERSION}.linux-amd64.tar.gz"
	mkdir -p $CONTAINERD_DOWNLOADS_DIR
	CONTAINERD_TGZ_TMP=$(echo ${CONTAINERD_DOWNLOAD_URL} | cut -d "/" -f 5)
	retrycmd_get_tarball 120 5 "$CONTAINERD_DOWNLOADS_DIR/${CONTAINERD_TGZ_TMP}" ${CONTAINERD_DOWNLOAD_URL} || exit $ERR_CONTAINERD_DOWNLOAD_TIMEOUT
	}

From cri-containerd repo:

Note: The standalone cri-containerd binary is end-of-life. cri-containerd is transitioning from a standalone binary that talks to containerd to a plugin within containerd. This github branch is for the cri plugin. See standalone-cri-containerd branch for information about the standalone version of cri-containerd.

I already have some packaging for containerd, but have not tested extensively or finalized the pipeline to publish such packages.

[CecileRobertMichon]

Thanks @cpuguy83. Is this ready to be fixed or do we need to wait for

I already have some packaging for containerd, but have not tested extensively or finalized the pipeline to publish such packages.

?

[cpuguy83]

We could use the version of containerd that we package with our moby packages, and it may even be worth it to have access to docker (for users) in the containerd-based setups.