Add support for Scaleway in Kops

/kind feature

We would like to deploy and manage Kubernetes clusters on Scaleway infrastructure using Kops so that our customers who want to manage their cluster themselves can do it easily with Kops.

ORIGINAL POST: We at Scaleway would like to add support in Kops for our Kapsule product so that our users are able to deploy their cluster easily with Kops.

No files, tests, or entry points are named. Start by reviewing how kOps supports existing infrastructure providers and how Scaleway's Kapsule product should map to cluster deployment and management; done means users can deploy and manage Kubernetes clusters on Scaleway through kOps.

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