[Feature] adding transform functionality

[otacilio-psf]

As in PySpark, the transform functionality allows you to split your transformations into units of work, creating a function for each, and then call them on your DataFrame, enabling the ability to chain transformations.

Having your transformations as functions helps in unit testing them.

def bussines_rule_1(df):
    df = (
        df
        .with_column(......)
        .with_column(......)
        .with_column(......)
    )
    return df
    
def bussines_rule_2(df):
    df = (
        df
        .with_column(......)
        .with_column(......)
    )
    return df

df = (
    df
    .transform(bussines_rule_1)
    .transform(bussines_rule_2)
)

PR with the changes: #2498

PySpark reference