Add agent for OVH Cloud (REST API)

[cymen]

This adds an agent for the OVH Cloud servers via the REST API. The REST API uses Oauth for authentication. Because of the authentication method, the agent ends up expecting an application key, an application secret and a consumer key or token. Getting/creating these values is explained at First Steps with the API. When creating the consumer key or token, it's important to select the option that disables expiration of it. Noting this here as it was unclear where this kind of documentation should go.

I'm also a bit unclear on the metadata aspect however I've implemented both on and off (with polling to verify status before it exits with return value 0 or 1).

[knet-ci-bot]

Can one of the admins verify this patch?

[cymen]

It's failing CI now on absence of tests/data/metadata/fence_ovh_cloud_rest.xml. Is that a hand created file or should the metadata part (that I mentioned being confused about above) be implemented and then this is generated?

Updated: figured that out -- that last bit of the doc at FenceAgentAPI hinted at what to do.

[oalbrigt]

You can run "make xml-upload" to generate/update this.