AST 1202 adp connector

Create ADP Connector

Implement a Prefect connector for ADP API integration, handling authentication and API operations for employee data retrieval.

Key details:

• Create in common/connectors/adp.py
• Use httpx.Client for HTTP operations (not requests library)
• Implement context manager pattern (__enter__/__exit__)
• Accept credentials as parameters to __init__ (API keys, OAuth tokens, etc.)
• Credentials passed from workflow task (loaded from AWS Secrets Manager)
• Return raw dict responses (validation at task boundaries)
• Set reasonable timeouts (30s default)
• Use raise_for_status() for HTTP error handling
• See common/connectors/pokemon.py for reference pattern