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?

[s-heppner]

I did some research and found:

Constraint AASa-001: The value of the cursor query parameter must not be empty. If the client does not know the cursor value, it must omit the whole query parameter in the request.

But this is with regards to how the client needs to form the request, not how the server needs to respond.