Test `same.dataset` functionality, including IPFS, and document on website.

[Bubblyworld]

E         Traceback (most recent call last):
E           File "/tmp/tmp.ClICOgrRSi", line 143, in <module>
E             _outputs = same_step_000_8a97fcbc0b5f4fb8ad0998ace9074930_fn(**_parsed_args)
E           File "/tmp/tmp.ClICOgrRSi", line 121, in same_step_000_8a97fcbc0b5f4fb8ad0998ace9074930_fn
E             exec(user_code, globals(), globals())
E           File "<string>", line 339, in <module>
E           File "/usr/local/lib/python3.10/site-packages/sameproject/sdk/dataset.py", line 30, in dataset
E             reader = _get_pandas_reader_for(url)
E           File "/usr/local/lib/python3.10/site-packages/sameproject/sdk/dataset.py", line 60, in _get_pandas_reader_for
E             return getattr(pd, extensions[extension])
E         KeyError: ''

The dataset(...) function doesn't seem to like being given files with no suffix... but we should probably support this in some way.

[Bubblyworld]

Other things that need to be fixed:

• we need to inject same.yaml and SAME_ENV into each step's container since the sdk needs the context
• we need to actually use the SAME_ENV when deciding which docker image to user