Write a wrapper for a fortmatic provider

[martyall]

We need a ps-web3 wrapper for the fortmatic provider. We already have a few examples for how to wrap providers

• https://github.com/f-o-a-m/purescript-web3-provider-engine
• https://github.com/f-o-a-m/purescript-uport
• https://github.com/f-o-a-m/purescript-web3-ledger-subprovider
• https://github.com/f-o-a-m/purescript-web3/blob/master/src/Network/Ethereum/Web3/Types/Provider.purs

[charlescrain]

https://github.com/blinky3713/internet-faucet/tree/feature/purescript-fortmatic