feat: Add aggregation capabilities for pandas DataFrameBaseView

[PatrykWyzgowski]

Feature description

Implement aggregation mechanism for DataFrameBaseView. It is marked with TODO in pandas_base.py file in this PR:

async def apply_aggregation(self, aggregation: IQLQuery) -> None:
    """
    Applies the aggregation of choice to the view.

    Args:
        aggregation: IQLQuery object representing the aggregation to apply
    """
    # TODO - to be covered in a separate ticket.`

Motivation

Currently single aggregation is supported by SqlAlchemyBaseView, though its parent MethodsBaseView (also a parent for DataFrameBaseView) posseses and interface for this. To unify capabilities of the most high-level views implemented (for SQLAlchemy and Pandas respectively) one should implement aggregation mechanism for DataFrameBaseView as well.

Additional context

No response

[micpst]

This will be implemented in #62