server/app/interfaces: update AAS- and SubmodelRepository API to V3.1

[Frosty2500]

This PR updates the AAS- and SubmodelRepository servers from version 3.01 to version 3.1 and fixes some bugs.

[s-heppner]

We need to wait with merging this PR until we release v2.0.0.

[s-heppner]

I've updated this branch, the merge conflicts were quite complex due to the refactoring we did while this PR was already out.

Currently, there's a typing issue:

    @classmethod
    def _get_slice(cls, request: Request, iterator: Iterable[T]) -> Tuple[Iterator[T], int]:
        limit_str = request.args.get('limit', default="10")
        cursor_str = request.args.get('cursor', default="1")
        try:
            limit, cursor = int(limit_str), int(cursor_str) - 1  # cursor is 1-indexed
            if limit < 0 or cursor < 0:
                raise ValueError
        except ValueError:
            raise BadRequest("Limit can not be negative, cursor must be positive!")
        start_index = cursor
        end_index = cursor + limit
        items = list(itertools.islice(iterator, start_index, end_index + 1))
        has_more = len(items) > limit
        paginated_slice = iter(items[:limit])
        next_cursor = cursor + limit if has_more else None
        return paginated_slice, next_cursor

As it is implemented, it actually returns Optional[int] with next_cursor.
However, the endpoints that use this method do expect int.
Someone more experienced with the API spec should investigate how this method is supposed to behave and what we need to adapt.

Furthermore, @moritzsommer, could you review the repository.py file w.r.t. the ObjectStore refactor please?