[JCLOUDS-702] JCloud ProfitBricks provider implementation

Hi! This implements most of ProfitBrick's API. I look forward for your comments, suggestions, and revisions.
Since the ApiMetadata is no longer annotated (to avoid collisions with the provider when using the "provider-id" string), it can not be loaded by the ServiceLoader and won't be listed in the "all apis" list (which is OK). It is not a generic API, such as Nova or EC2, so we should just expose the provider.

You have to remove that ApiMetadata test and add one for the provider metadata. You can take the [DigitalOceanProviderMetadataTest](https://github.com/jclouds/jclouds-labs/blob/master/digitalocean/src/test/java/org/jclouds/digitalocean/DigitalOceanProviderMetadataTest.java) as an example.