feat(dbt): add EAS source and staging model (#2322)

warehouse/dbt/models/ethereum_attestation_service_sources.yml

@@ -0,0 +1,7 @@
+sources:
+  - name: ethereum_attestation_service_optimism
+    database: opensource-observer
+    schema: ethereum_attestation_service_optimism
+    tables:
+      - name: attestations
+        identifier: attestations

warehouse/dbt/models/staging/ethereum_attestation_service/stg_ethereum_attestation_service__optimism.sql

@@ -0,0 +1,19 @@
+select
+  id,
+  attester,
+  recipient,
+  ref_uid,
+  schema_id,
+  decoded_data_json,
+  revocable,
+  revoked,
+  is_offchain,
+  txid as transaction_hash,
+  timestamp_seconds(`time`) as `time`,
+  case
+    when expiration_time != 0 then timestamp_seconds(expiration_time)
+  end as expiration_time,
+  case
+    when revocation_time != 0 then timestamp_seconds(revocation_time)
+  end as revocation_time
+from {{ source("ethereum_attestation_service_optimism", "attestations") }}