Get login token from Bango (bug 898082)

WiP, need to be discussed:

* [x] logic of resources (bango API vs. solitude API)
* [x] credentials to be able to test with `bango-basic.py`
* [x] is `password` the same as the one used to log in on the marketplace website?
* [x] difference between `username`, `emailAddress` and `personId`