Expose a Decimal32Dtype in cuDF Python

[skirui-source]

Fixes: #8218

Similarly to libcudf's 64-bit decimal type, this PR exposes the Decimal32Dtype and its corresponding Decimal32Column type. Following this implementation, user can create a series or dataframe with decimal32 dtype.
Note: Only to_arrow and from_arrow methods are currently being supported.

Example:

>>> import cudf
>>> s = cudf.Series([1,2,3,4], dtype=cudf.Decimal32Dtype(precision=8, scale=2))
>>> s
0    1.00
1    2.00
2    3.00
3    4.00
dtype: decimal32

[isVoid]

Mostly looks good aside one small question. Great job!

[charlesbluca]

Looks great 🙂 just one small question

[codecov]

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[isVoid]

lgtm code wise. Great job!

Can you also update this page to include the new datatype? https://docs.rapids.ai/api/cudf/stable/basics.html

[skirui-source]

@gpucibot merge