Export all chains

[sbauch]

When wagmi is used with rainbowkit, it seems that rainbowkit will force the user to switch to the first network listed in the array passed to configureChains, but only if the user is currently connected to a network that is not included in that list.

I prefer to use and write dapps that only ask the user to switch to the network when absolutely necessary - i.e. submitting a transaction.

In order to achieve this UX with wagmi and rainbowkit, I import individually every network exported by the chains package. It would be a nice convenience to be able to import allChains in an array such that i dont have to manually update my list as new chains are added.