Add `Fortmatic` support

[auryn-macmillan]

Payout

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Description

Issue owner: raul@colony.io

We would like to support Fortmatic with this library. For that a purser-fortmatic module should be created that allows for easy wallet access using purser.

This issue is considered done when:

• A purser-fortmatic module is created that is (presumably) using the fortmatic sdk.
• The wallet implements the purser Common Wallet Interface
• A test suite is added for this module (see https://github.com/JoinColony/purser/tree/master/modules/tests)
• A video is provided presenting a login flow with purser using the purser-fortmatic module

[PumpkingWok]

Hi there, I'm going to start to look in it, thanks in advance.