Implement BiontyField

[Zethson]

class BiontyField():

    def __init__(parent: Entity, name: str):
            self.parent = parent
            self.name = name

    def __repr__():
            return self.name

# rename Entity to Bionty
class Bionty:
        def __init__():
                for col_name in self.df().columns:
                        setattr(self, col_name, BiontyField(self, col_name))