Use Brightbox::Config object to configure services

In https://github.com/fog/fog-core/commit/2528270ce9c931c492b90f7de6a202645b38cb08 we added support for passing in a configuration object into a new service.

This object ignores the contents of the `Fog.credentials` global and can be shared between two services to allow things like tokens to be kept in sync. This was difficult and hacky when services expected high level credentials (like client ID and secret) and would do it's own authentication.

This doesn't scale to multiple services where credentials and access tokens may be shared and expiring an OAuth token used for our main API (which currently spans fog's Compute and LoadBalancer) services should be in sync.

We're currently waiting on the `fog-core` release to reference the gem by it's (probable) `v1.22.0` version to lock the functionality in.