feat: add SystemCgroup option to containerd runtime options

update `README.md`, `conformance-tests/README.md`, `node-installer/script/installer.sh`
to include `SystemdCgroup` option in containerd runtime options.

Signed-off-by: Jiaxiao (mossaka) Zhou <[email protected]>

Author: Mossaka

README.md

@@ -66,14 +66,18 @@ To carry out the installation step-by-step, do the following:
 
     ```toml
     [plugins."io.containerd.cri.v1.runtime".containerd.runtimes.spin]
-    runtime_type = "io.containerd.spin.v2"
+      runtime_type = "io.containerd.spin.v2"
+    [plugins."io.containerd.cri.v1.runtime".containerd.runtimes.spin.options]
+      SystemdCgroup = true
     ```
 
     Otherwise, add:
 
     ```toml
     [plugins."io.containerd.grpc.v1.cri".containerd.runtimes.spin]
-    runtime_type = "io.containerd.spin.v2"
+      runtime_type = "io.containerd.spin.v2"
+    [plugins."io.containerd.grpc.v1.cri".containerd.runtimes.spin.options]
+      SystemdCgroup = true
     ```
 
     The [Node Installer script](./node-installer/script/installer.sh) that is used by the [`runtime-class-manager`](https://www.spinkube.dev/docs/topics/architecture/#runtime-class-manager) does this for you and is a good reference to understand the common paths to the containerd configuration file for popular Kubernetes distributions.

conformance-tests/README.md

@@ -19,6 +19,8 @@ Containerd must be configured to access the `containerd-shim-spin`:
     ```toml
     [plugins."io.containerd.grpc.v1.cri".containerd.runtimes.spin]
         runtime_type = "/usr/bin/containerd-shim-spin-v2"
+    [plugins."io.containerd.grpc.v1.cri".containerd.runtimes.spin.options]
+        SystemdCgroup = true
     ```
 3. Restart containerd if it is running as a service
     ```sh

node-installer/script/installer.sh

@@ -42,6 +42,8 @@ if ! grep -q spin $NODE_ROOT$CONTAINERD_CONF; then
     echo '
 [plugins."io.containerd.grpc.v1.cri".containerd.runtimes.spin]
     runtime_type = "'$KWASM_DIR'/bin/containerd-shim-spin-v2"
+[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.spin.options]
+    SystemdCgroup = true
 ' >> $NODE_ROOT$CONTAINERD_CONF
     rm -Rf $NODE_ROOT$KWASM_DIR/active
 fi