Implement Ethereum Asset (Addresses, ERC20, ERC721) Widgets

[lucasvo]

We need a set common widgets to use in our UIs that represent ERC20 and ERC721 assets, balances and amount both to modify and read values.

Decimal Widgets:

• It's important that they don't round any inputs and have arbitrary precision (that goes beyond javascript's standard 64bit numbers)
• You should be able to specify a number of digits to display with a property

The bold text is the widget description and not part of the wireframe of the widget

It might be worthwhile to look into how gnosis safe implemented some of their widgets: https://github.com/gnosis/safe-react