Bug 1098515 - [Usage][Tests] Prepare the ground for MarionetteJS integration tests. r=salva

Thinking more about this, I think that what you're describing is just different FTE flows that should be tested too, so I've just added two more tests for the prepaid and postpaid plans and made test suite names more descriptive. So I'm checking now that FTE iframe is hidden as you suggested + that appropriate tab is visible (for non-configured - DataUsage tab, for prepaid - Balance tab, for postpaid - Telephony Tab)