Add Ergo Platform blockchain

[TheStophe]

For future blockchains to be added, please consider adding Ergo Platform.

It's a GPU PoW chain highly regarded in the Cardano community. A smaller cap project but an interesting case study because it has a pool mining MAV of 2.

https://ergoplatform.org/en/

[LadyChristina]

Hi @ccgarant, thanks for the suggestion! For the time being we use block data collected from Google's Big Query and since Ergo is not supported there we cannot add it either, but we will keep the suggestion in mind for when we stop relying on Big Query.