east-dynamodb: DynamoDB adapter for east migration tool

AWS DynamoDB adapter for the east migration tool (version 1.0.1, stable). It relies on AWS SDK v3 and provides a plugin to run database migrations on DynamoDB tables with composite primary keys. Key differentiators: lightweight, no transactions (DynamoDB limitation), supports environment variable configuration, and requires manual installation of peer dependencies (@aws-sdk/client-dynamodb and @aws-sdk/util-dynamodb). Release cadence: infrequent updates. Compared to alternatives like dynamodb-migrate or node-dynamodb-migrate, east-dynamodb integrates tightly with east's migration framework.