dagster: create asset for indexing EAS data

[ccerv1]

Describe the feature you'd like to request

We'll probably just want to start by dumping raw attestation data into a data lake

Describe the solution you'd like

A crawler similar to the open_collective.py example that fetches attestations from the EAS graphql endpoint and dumps that standard data plus a JSON with the decoded schema data into BigQuery.

Here's an example: https://gist.github.com/ccerv1/12a83e4a698a200a48ac17b97b049241

Describe alternatives you've considered

Ask the EAS team if we can get a mirror of their database