v3.0.0a Pydantic V2 migration

Pydantic v1 stops working with python 3.14 (Pi-thon 🐍)

This release contains the migration of the old v1 models into a .legacy module
While replacing them with the same models, but built on top of pydantic v2

Not a complicated migration and tests do pass, but in case of any issues - feel free to issue a bug report

Full Changelog: v2.1.1...v3.0.0a2