-----
**Main change**: Database model
Cleaned database model.
Changes
*******
- We are now using the modern version of SQLAlchemy Mapped syntax
- We have 4 tables now: Dataset, Experiment, Model and Run
- Dataset One-to-Many Experiment
- Experiment One-to-Many Model
- Model One-to-One Run
- Model and Run cascades on deletion.
- Added states for the future state machine.