Replace Sokol by Chiado as Gnosis Chain testnet

[hbarcelos]

Linguo still using Sokol as Gnosis Chain testnet, however the offical post-merge testnet is Chiado.

Linguo contracts need to be deployed on Chiado and all references to Sokol must be relpaced in the dapp.

[gratestas]

TheGraph does not support the Chiado network atm. We will provide support for it once it becomes available.