New feature: Instance configuration service

[ichinaski]

Overview

Set up a new (standalone) service, allowing the FLOW app to retrieve the configuration tokens for a particular instance.

This service belongs to the single FLOW app feature:

• Design repo issue
• akvo-flow issue (TODO)
• akvo-flow-mobile issue (TODO)

[ichinaski]

The last digit of the code will always be a control digit, using http://en.wikipedia.org/wiki/Luhn_algorithm to calculate it. This way the device can figure out whether the code was correctly typed or not, before issuing the request to the API

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.