Implementing VD4RL

[AntreasAntoniou]

Implement VD4RL datasets into GATE, and write tests.

Refer to

• Dataset template: https://github.com/BayesWatch/RL-GATE/blob/main/gate/data/image/classification/happywhale.py
• Test template: https://github.com/BayesWatch/RL-GATE/blob/main/tests/data/image/classification/test_happy_whale_dolphin.py

For examples.

[AntreasAntoniou]

@trevormcinroe Have a chat with Adam, and I am sure you can quickly adapt to this and make faster progress.