proposal: CRI-O to graduation

[haircommander]

CRI-O has been an incubating project for 3 years, and has been adopted by a number of organizations for their implementation of the Kubernetes container runtime interface. The CRI-O community believes it's graduation time :sunglasses:

@haircommander will be the main contact here.

TIA for your time and attention

[haircommander]

cc @saschagrunert @mrunalp @angellk