Reduce Factory duplication

[faustbrian]

https://github.com/ArkEcosystem/platform-sdk/blob/master/packages/platform-sdk-ark/src/factory.ts

The factory that is provided by every package has quite a bit of duplication. Instead of each package shipping with its own factory, there will be a CoinFactory that handles the instantiation of the coin implementations.

import { CoinFactory } from "@arkecosystem/platform-sdk";
import ARK from "@arkecosystem/platform-sdk-ark";

await CoinFactory.construct(ARK, { ... });

This will reduce duplication quite a bit and reduce the overhead of what the coin implementations have to maintain.