OpenML connector for MLModels

[Taniya-Das]

OpenML connector for fetching OpenML flows to AIoD ml models.
Note:

1. All sklearn pipelines are ignored while fetching flows from OpenML. ToDo: discuss how to handle pipelines. Bonus: only fetch pipelines which have >= 1 run on OpenML.
2. improve mlmodel.name (current implementation - openml.flow.name which might not be very clean).
3. Discuss how to save flow parameters in Aiod.
4. Discuss where to save language (human language) of flow (maybe ai_resource.metadata_language).

[Taniya-Das]

ToDo (after PR #204 approval):

1. define "creator" as a dynamic class using resource_create.

[josvandervelde]

Thanks! Looks good, some comments. While running it, we got a weird KeyError: 'last_id' error, let's see if we can fix that as well.

[Taniya-Das]

To resolve 'last_id' error, handled cases when the item is ResourcewitrhRelations type or RecordError type.

[josvandervelde]

Two comments, other than that I'd be happy to merge!

I don't think there is value already in this functionality (I don't think the user can use the current metadata), but it's fine for a start.
We might deploy this on the aiod-dev instance, and discuss integration with RAIL.

[josvandervelde]

Thanks! Looks good to me