:zap: Migrate to Lightning and Hydra

[kaylode]

• [x] Use Lightning as Pytorch training template
• [x] Use Hydra for complex configuration management

Comments:

• Luckily (and suprisingly), the old codebase of Theseus bears a striking resemblance to both Lightning Callbacks and Hydra Configuration so the migration took little effort to accomplish.
• However, better structure should be considered if want to integrate ML training 🤔