Change data_kind from 'individual_electrons' to 'extracted_electrons'

[cfuselli]

We introduced an inconsistency in the data kinds in the #264 PR.
We have that PropagatedElectrons and Extracted electrons had the same data kind, but different number of rows (because in the second one we kept only the extracted electrons, roughly 50% of the total propagated ones). This was not really showing up anywhere, because the PropagatedElectrons has as a unique parent that is ExtractedElectrons, and no other plugins ever tried to put the two together.

What is proposed here is to just introduce a new data kind for ExtractedElectrons (and delayed ones).
Other option I can think of is to just merge ElectronPropagation and ElectronExtraction and just never save the details of positions of the electrons that won't be extracted.

Plugin attribute standardization:

• Changed data_kind from individual_electrons to extracted_electrons in both ElectronExtraction and ExtractedElectronsMerger classes to ensure consistent naming for extracted electron data. [1] [2]
• Updated data_kind from delayed_individual_electrons to delayed_extracted_electrons in DelayedElectronsExtraction for clearer distinction of delayed extracted electrons.

Version updates:

• Incremented version numbers in all affected plugins to reflect these attribute changes: ElectronExtraction to 0.4.0, DelayedElectronsExtraction to 0.0.3, and ExtractedElectronsMerger to 0.0.3. [1] [2] [3]

[cfuselli]

Missing changing the types in all the compute functions still