Profile configuration file for API and CLI

[thenno]

#90

Added support for profiles to python sdk / cli's config.

Example:

{
    "config_version": 2,
        "profiles": {
            "profile1": {
            "token": "token1"
        },
        "profile2": {
            "token": "token2"
        }
    }
}

Default values has not been implemented because we didn't agree on what they should look like.
The old approach without profiles still remains.

[dmi-feo]

maybe ~/.yt/config and expandpath later? this relative path looks a bit confusing

[thenno]

decided to rename it