Instead of asking the user to change the network, we ask the wallet software to change the chain

[asgeir-s]

Instead of asking the user to change the network (chain), we can ask the wallet software to change the chain.

Separated from #56 into this issue.

Notes

• Sometimes, there is more than one "correct" network to change to.
• Only when connecting a wallet to an already open publication do we know what network should be connected to.

Implementation

• EIP-3326: wallet_switchEthereumChain
• EIP-3085: wallet_addEthereumChain

Tasks

• [x] If there are multiple options: let the user select one of the supported networks. When one is selected/clicked, request the wallet software to change the network.
• [x] If there is one correct network: request the wallet software to change that network.
• [x] If the network (selected) is not added to the user's wallet software: request the wallet software to add the network, then request it to change to the new network (if it does not happen automatically).

[asgeir-s]

If we are going to request to add a chain to the user's wallet, we need to decide on a rpcUrls, chainName, blockExplorerUrls, etc., for each network.

@auryn-macmillan: should we just take the top RPCs (and other information) for each network from https://chainlist.org, or do you have a preference?

[auryn-macmillan]

Yes, I think using chainlist as a source of truth sounds like a very reasonable solution.