Add a page with supported networks and limitations

[ctrlc03]

Currently, it is not clear on which live networks MACI is supported, and which networks are best for its usage. For instance on Scroll we can only send three messages in a batch, whereas on Optimism we can send 83-84.

This should be a new entry in the documentation website

Requirements

• deploy contracts on OP/Arbitrum/Base
• Submit batches of messages to understand maximum values
• Store reusable contract addresses on https://maci.pse.dev/docs/developers-references/smart-contracts/DeployedContracts