User should be able to sort assets

[dnaidionov]

Both Grid View and List View should include sort controls.

Sort controls allow sorting assets by balance equivalent in USD/ETH descending or ascending, descending by default.

Sort does not change when users change between Grid and List views.

sketch file: https://sketch.cloud/s/gbDax

[burieberry]

@dnaidionov should this assets view be a new route (/assets)?