add Dataset.from_list

[sanderland]

As discussed in #4885

I initially added this bit at the end, thinking filling this field was necessary as it is done in from_dict.
However, it seems the constructor takes care of filling info when it is empty.

if info.features is None:
  info.features = Features(
      {
          col: generate_from_arrow_type(coldata.type)
          for col, coldata in zip(pa_table.column_names, pa_table.columns)
      }
  )

[HuggingFaceDocBuilderDev]

The documentation is not available anymore as the PR was closed or merged.

[sanderland]

@albertvillanova it seems tests fail on pyarrow 6, perhaps from_pylist is a v7 method? How do you usually handle these version differences?
Added something that at least works

[lhoestq]

Cool ! Thanks a lot :)

I added a few comments:

[lhoestq]

Thanks ! LGTM :)