Add scaleway provider to the examples

[mig4ng]

Why

I wanted to try this quickstart at Scaleway and it was not one of the examples. There is one PR (https://github.com/rancher/quickstart/pull/123) open for this but it was WIP and using an outdated version of scaleway/scaleway terraform provider.

What changed (to help with review)

I based it in the DigitalOcean example because they clouds and terraform providers are very similar.

Changes:

• region/zone by provider instead of per resource/instance
• public_ip attributes instead of ipv4
• ssh key/credentials are added to project instead of each instance
• image names and instance size/type

Also changed the README and the terraform.yml github workflow.

Tests

Tested it and the rancher server and a RKE example workload cluster started properly and everything seems to be working as expected.

Screenshots

[bashofmann]

Thank you for the contribution, and sorry for the long reaction time. The PR looks good and works.

Since there have been quite a few changes in the mean time, I rebased your changes on master and opened up a new PR.

Closing in favour of #197.