[HIL-SERL port] Add Reward classifier benchmark tracking to chose best visual encoder

[helper2424]

What this does

We create custom Resnet 10. Need to compare inference perfomance between old encoder/Resnet10 and FB Convnet to chose the best one.

This PR adds ability to track inference time.

Examples:

Title	Label
Fixes #[issue]	(🐛 Bug)
Adds new dataset	(🗃️ Dataset)
Optimizes something	(⚡️ Performance)

How it was tested

Explain/show how you tested your changes.

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• Added test_something in tests/test_stuff.py.
• Added new_feature and checked that training converges with policy X on dataset/environment Y.
• Optimized some_function, it now runs X times faster than previously.

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pytest -sx tests/test_stuff.py::test_something

python lerobot/scripts/train.py --some.option=true

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[AdilZouitine]

lgtm