Safe Dashboard: Gas fee over all networks for added safes

[usame-algan]

Overview

Part of #3693

As part of the dashboard, we want to create a module that displays network specific gas fees.

Requirements

Since absolute values are so volatile and very different from chain to chain, it's probably best to display a value relative to the 24h average on that chain. E.g. Gnosis Chain 130% – 0,0001 xDai.

TBD

[katspaugh]

Usame's notes: https://docs.google.com/document/u/1/d/1l6mwuWe19gqPjmzSIwWK3sJDS2Mk9xNLuPGoKlkAYkQ/edit?usp=sharing