Add support for diffuse IAM in the Array and PVSystem classes

[cbcrespo]

• Closes Support diffuse component-specific IAM in Array.get_iam() #2812
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This PR adds support for diffuse component-specific IAM in the Array and PVSystem classes, laying the groundwork for its later inclusion in the ModelChain class.

[adi-IL]

Signature mismatch between PVSystem.get_iam_diffuse and Array.get_iam_diffuse:

PVSystem.get_iam_diffuse accepts **kwargs and forwards them to each array:

return tuple(array.get_iam_diffuse(tilt, iam_model=iam_model,
                                   marion_model=marion_model, **kwargs)
             for array, tilt in zip(self.arrays, surface_tilt))

However, Array.get_iam_diffuse does not accept **kwargs:

def get_iam_diffuse(self, surface_tilt, iam_model='marion_diffuse',
                    marion_model=None):

Passing any optional keyword arguments to PVSystem.get_iam_diffuse raises TypeError: Array.get_iam_diffuse() got an unexpected keyword argument. Array.get_iam_diffuse should accept **kwargs and forward them to the underlying IAM model function.