Create an export script with metrics from NFT game run

[gabrielfior]

In addition to the data available in the DB (function_calls, messages exchanged, etc), we should collect some on-chain metrics before resetting the anvil container (and its balances and transactions). If we ever expand to multiple agents (incl. ones that we don't control), such data collection can be very useful.

Metrics include:
-> NFT transfers
-> Messages exchanged
-> Balances at every block

[kongzii]

@gabrielfior Can't this be in PMA, instead PMAT? It's nothing reusable in other repos, so no need to complicate stuff.