leftovers from initial development

[tormath1]

To have a first working version, I voluntary left some implementations to later. This issue will track those, feel free to grab one if you want to contribute (the list will be updated):

$ git grep -n TODO -- :^vendor | awk '{ print "- [ ] " $0 }'

• provider/helper.go:46: // TODO: Add OSType, OSName, OSVersion and OSArch.
• provider/provider.go:115: // TODO: Implements p.cli.StopInstance(ctx, instance, force).