Need support for multiple versions of contracts and balance contracts

[petermunnings]

Currently there is only support for version 1. This needs to be updated.

The idea is that a new collection needs to be created in Mongo that will track the current version of a contract and the link to its balance contract (along with the balance contract version)

i.e.
contractName: JoeBloggTestToken
contractVersion: 2
balanceContractName: JoeBloggTestBalance
contractVersion: 1

Those contracts and versions would reference the contract collection where the address/abi etc would be stored.

In order to update this from the UI, a contract management screen would need to be created where the contracts could be updated and deployed. Because this is currently for demonstration purposes version 1 of the contract is adequate