Initialize `Series` of `dtype=pl.Decimal` directly from list of python `int`s

[sslivkoff]

Problem description

It would be nice to be able to do this:

numbers = [2963091539321097135000000000, 25658709114149718824803874]
pl.Series(numbers, dtype=pl.Decimal)

But doing so raises ComputeError: unable to convert any-value of dtype f64 to decimal.

So instead it is necessary to manually convert to decimal first. Running pl.Config.activate_decimals() does not remove the error

[sslivkoff]

It looks an error only happens when using large ints. This works without error:

numbers = [1, 2]
pl.Series(numbers, dtype=pl.Decimal)

[alexander-beedie]

This throws an error as Python has large integer support, but to interop with Rust it has to convert values > Int64 to Float64, which almost always guarantees a loss of precision - at which point you don't have the value you thought you had. I think it's reasonable to expect decimals as input here as the error prevents a worse scenario ;)

[alexander-beedie]

(Actually, I'll keep it open for now in case we can leverage i128 conversions in the future 🤔)