Make it possible to display asset values in ETH

#Description
As a user, I would like to be able to see non-Ether based assets denominated in ETH rather than fiat.

#Situation
Given that I have non-Ether assets associated with an address,
When I look at wallet view, transaction details, or other places in app that are presented in USD by default,
Then I would like to be able to change app settings to diplay assets denominated in ETH.

**Acceptance Criteria**
Non-Ether asset values converted to ETH denomination rather than fiat.

Start by locating the app settings plus the wallet view and transaction details where asset values are presented in USD. Implement the setting so non-Ether asset values can be displayed in ETH, and verify the acceptance criterion across those views.

Written by the indexing model from the issue text.