[CBBS] Use Go style type/constant names

What's the issue?
IMO the backup service names lots of variables in a backward fashion, for example:

AWSCloudProvider (which is of type 'CloudProvider')

In my opinion, this should be:

CloudProviderAWS

I think this for two reasons:
1) It appears to be the general consensus with popular Go libraries (and is used internally e.g gocb/gocbcore)
2) For newcomers, it's far easier to find the enumerations using auto-completion (by name)