gVisor: initial support for gVisor container runtime (#7661)

* Docker/Containerd: move downloads urls to containerd-common

* gVisor: initial support for gVisor container runtime

roles/container-engine/gvisor/molecule/default/converge.yml

@@ -0,0 +1,11 @@
+---
+- name: Converge
+  hosts: all
+  become: true
+  vars:
+    gvisor_enabled: true
+    container_manager: containerd
+  roles:
+    - role: kubespray-defaults
+    - role: containerd
+    - role: gvisor