Provide chain & relayer JSON configurations in repo

[jurevans]

It would be nice & useful if we had something like the Prax Registry at https://github.com/prax-wallet/registry/

Example

Chain IDs with available IBC relayer details: https://github.com/prax-wallet/registry/blob/main/registry/chains/penumbra-1.json

This would enable a simpler way of adding any default chain data, and we could use it to allow users to switch networks more easily in Namadillo. We could populate it with Housefire & Campfire details, but allow the use of custom values (such as for our internal devnet)