Add support for more networks to the app

[asgeir-s]

To see the currently supported chains (for the UI) see: https://github.com/gnosis/zodiac-safe-app/blob/5e2174d1d7b2a4c12d3c9c8fdd4b5b03be239219/packages/app/src/utils/networks.ts#L1

For this task, we need to add more networks to the UI, test the app and verify that everything works (or figure out what's missing).

Networks to add:

• Arbitrum
• Optimism
• @auryn-macmillan: what more chains?

[auryn-macmillan]

@manboy-eth, ideally we should support all networks that are fully supported by the Gnosis Safe (see the screenshot below).
However, the following are sufficient for now:

• Ethereum Mainnet
• Gnosis Chain
• Goerli
• Optimism
• Arbitrum
• BSC
• Avalanche

Full list of safe supported chains: