Serialization Of Map and Model Classes into ASDF format

Gammapy currently serializes its data products across multiple data formats, which creates a fragmented workflow with poor metadata handling. This project introduces the Advanced Scientific Data Format (ASDF) for Map and Model objects. ASDF is transparent, human-readable, easily extensible, and supports schemas and validation machinery. This project implements ASDF converters and schemas for Gammapy data objects. The resulting ASDF support provides Gammapy users with a unified, self-describing file format that improves reproducibility and simplifies data sharing across the community.