Add SMTWTP env

[henry-yeh]

Description

Add SMTWTP env and its env embeddings.

Types of changes

What types of changes does your code introduce? Remove all that do not apply:

• New feature (non-breaking change which adds core functionality)

Checklist

Go over all the following points, and put an x in all the boxes that apply.
If you are unsure about any of these, don't hesitate to ask. We are here to help!

• My change requires a change to the documentation.
• I have updated the tests accordingly (required for a bug fix or a new feature).
• I have updated the documentation accordingly.

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Files	Coverage Δ
rl4co/envs/__init__.py	95.00% <100.00%> (+0.26%)	⬆️
rl4co/models/nn/env_embeddings/context.py	97.70% <100.00%> (+0.26%)	⬆️
rl4co/models/nn/env_embeddings/dynamic.py	95.45% <ø> (ø)
rl4co/models/nn/env_embeddings/init.py	99.15% <100.00%> (+0.09%)	⬆️
rl4co/utils/test_utils.py	93.93% <100.00%> (+0.39%)	⬆️
rl4co/envs/smtwtp.py	98.63% <98.63%> (ø)

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[fedebotu]

Great job! Thanks for adding the tests, merging now 🚀