Case insensitive sorting

[Rivosoa]

Hi, to make case insensitive sorting in mongodb we need to use collation.
I couldn't find anything about collation in the documentation. I found a solution here #111 (comment) but it still gave me a little struggle to make it work. I'm not sure if I did it correctly but it works.

I think beanie should have an easier way for doing case insensitive sorting.

Here's how I made my code work by following the solution I linked above

class MyDocument(Document):
    # ...
    
    @classmethod
    def find_insensitive(
        self,
        *args: Optional[
            Union[
                str, Tuple[str, SortDirection], List[Tuple[str, SortDirection]]
            ]
        ]
    ):
        custom = CustomFindMany(self)
        custom.collation(Collation(locale='en'))
        return custom.find_many(*args)


class CustomFindMany(FindMany):
    def init(self, instance: FindMany):
        self.parent = instance
        self.collation_expressions = None

    def collation(self, collation):
        if collation is not None:
            self.collation_expressions = collation
        return self

    def __getattr__(self, name):
        return getattr(self.parent, name)

    @property
    def motor_cursor(self):
        return self.document_model.get_motor_collection().find(
            filter=self.get_filter_query(),
            sort=self.sort_expressions,
            projection=get_projection(self.projection_model),
            skip=self.skip_number,
            limit=self.limit_number,
            collation=self.collation_expressions,
            session=self.session,
        )

And then I call MyDocument.find_insensitive().sort(MyDocument.name)