Enable crun support on CRI-O

[electrocucaracha]

What type of PR is this?

Uncomment only one /kind <> line, hit enter to put that in a new line, and remove leading whitespaces from that line:

/kind api-change
/kind bug
/kind cleanup
/kind design
/kind documentation
/kind failing-test

/kind feature

/kind flake

What this PR does / why we need it:
This change provides instructions to install and configure crun. This container runtime has lower footprint, better performance and cgroup2 support among other things.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:
The current implementation is only offered for CRI-O thru the crun_enabled configuration value.

container_manager: crio
crun_enabled: true

Once the cluster is deployed is possible to create workloads like the following:

apiVersion: v1
kind: Pod
metadata:
  name: crun-pod
spec:
  runtimeClassName: crun
  containers:
    - name: test
      image: busybox
      command: ["sleep"]
      args: ["infity"]

and the assigned worker node will show the follows:

$ ps -ef | grep crun
root       21406       1  0 16:28 ?        00:00:00 /usr/bin/conmon -b /var/run/containers/storage/overlay-containers/c1e62f2a41ede66645a2178c1eafb51a8035aff88fef4c1edc2856428d8211d1/userdata -c c1e62f2a41ede66645a2178c1eafb51a8035aff88fef4c1edc2856428d8211d1 --exit-dir /var/run/crio/exits -l /var/log/pods/default_crun-pod_deb438b6-76a8-4fd0-abda-777a922c4c70/c1e62f2a41ede66645a2178c1eafb51a8035aff88fef4c1edc2856428d8211d1.log --log-level info -n k8s_POD_crun-pod_default_deb438b6-76a8-4fd0-abda-777a922c4c70_0 -P /var/run/containers/storage/overlay-containers/c1e62f2a41ede66645a2178c1eafb51a8035aff88fef4c1edc2856428d8211d1/userdata/conmon-pidfile -p /var/run/containers/storage/overlay-containers/c1e62f2a41ede66645a2178c1eafb51a8035aff88fef4c1edc2856428d8211d1/userdata/pidfile --persist-dir /var/lib/containers/storage/overlay-containers/c1e62f2a41ede66645a2178c1eafb51a8035aff88fef4c1edc2856428d8211d1/userdata -r /usr/bin/crun --runtime-arg --root=/run/crun --socket-dir-path /var/run/crio -u c1e62f2a41ede66645a2178c1eafb51a8035aff88fef4c1edc2856428d8211d1 -s
root       21469       1  0 16:28 ?        00:00:00 /usr/bin/conmon -b /var/run/containers/storage/overlay-containers/37a3aa028967d8ae1028ed618152bdd25016f91971135985ae9b02d823e2d095/userdata -c 37a3aa028967d8ae1028ed618152bdd25016f91971135985ae9b02d823e2d095 --exit-dir /var/run/crio/exits -l /var/log/pods/default_crun-pod_deb438b6-76a8-4fd0-abda-777a922c4c70/test/0.log --log-level info -n k8s_test_crun-pod_default_deb438b6-76a8-4fd0-abda-777a922c4c70_0 -P /var/run/containers/storage/overlay-containers/37a3aa028967d8ae1028ed618152bdd25016f91971135985ae9b02d823e2d095/userdata/conmon-pidfile -p /var/run/containers/storage/overlay-containers/37a3aa028967d8ae1028ed618152bdd25016f91971135985ae9b02d823e2d095/userdata/pidfile --persist-dir /var/lib/containers/storage/overlay-containers/37a3aa028967d8ae1028ed618152bdd25016f91971135985ae9b02d823e2d095/userdata -r /usr/bin/crun --runtime-arg --root=/run/crun --socket-dir-path /var/run/crio -u 37a3aa028967d8ae1028ed618152bdd25016f91971135985ae9b02d823e2d095 -s
$ sudo crun --version
crun version 0.15
commit: 56ca95e61639510c7dbd39ff512f80f626404969
spec: 1.0.0
+SYSTEMD +SELINUX +APPARMOR +CAP +SECCOMP +EBPF +CRIU +YAJL
$ sudo crun list
NAME                                                             PID       STATUS   BUNDLE PATH                            
c1e62f2a41ede66645a2178c1eafb51a8035aff88fef4c1edc2856428d8211d1 21416     running  /run/containers/storage/overlay-containers/c1e62f2a41ede66645a2178c1eafb51a8035aff88fef4c1edc2856428d8211d1/userdata
37a3aa028967d8ae1028ed618152bdd25016f91971135985ae9b02d823e2d095 21477     running  /run/containers/storage/overlay-containers/37a3aa028967d8ae1028ed618152bdd25016f91971135985ae9b02d823e2d095/userdata

Does this PR introduce a user-facing change?:

[k8s-ci-robot]

Hi @electrocucaracha. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[floryut]

/ok-to-test
/approve

Would be nice to have a crio test using crun though.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: electrocucaracha, floryut

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[LuckySB]

/lgtm