Pass current opts dictionary to `vm_profiles_config` and `cloud_providers_config`. This will help unifying profiles with providers.
ALL configuration parsing, merging and unification is now done in `saltcloud.config`.
One step further. Refs #546

* All cloud profile now has it's provider set as `<alias>:<driver>`. This is done when loading the configuration.
* All cloud providers settings now include a `profiles` key for each of it's driver which included every profile that is using the `<alias>:<driver>`. This is done when loading the configuration.
* Cloud profiles are no longer stored as `vm` in the internal configuration dictionary. It's `profiles` now.
* Fixed the `ec2` driver because of how the data is laid out now.
* Fixed the `get_config_value` config helper, also because of how data is laid out now.