Add ability to have multiple profiles in the .bbrc

[dmitrisweb]

Example of .bbrc file:

{
    "scheme": "http",
    "host": "localhost",
    "context": "portalserver",
    "port": "80",
    "username": "admin",
    "password": "admin",
    "profiles": {
        "dev": {
            "host": "winter-water-81-dbp.backbase.dev"
        }
    }
}

Profile properties will be merged to the root level properties.

Usage: bb import-item --profile=dev

or save it as environment variable: export BBPROFILE=dev

and use without using profile flag: bb import-item

[salvitas]

niceee!! i have been wanting to do that for some time but never found time to do it ;)

[dmitrisweb]

@igord can you pls review and merge?