Badges XBlock Service

[Kelketek]

Description: Provides an XBlock service that exposes Badging functionality to XBlocks.
Jira: https://openedx.atlassian.net/browse/SOL-1363
Discussion/Spec: https://docs.google.com/document/d/1ob-leRHV97agPGw5ys9uASXrcsU8qf51bzYlKH3mBEM/edit?usp=sharing
Dependencies: https://github.com/edx/edx-platform/pull/10498

@smarnach Only the most recent commit is up for review here-- all the previous ones are from the dependency PR.

[openedx-webhooks]

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[smarnach]

@Kelketek This looks good apart from the one comment I added.

[smarnach]

Looking good now. 👍 once the build passes.

The Python build was red with status "aborted" and no reported test failures – not sure what that means, so I just triggered a new run.

[Kelketek]

@nedbat I've applied fixes for your notes. Is there anything else you need to see here or can I get a +1 from you on this part of the feature branch?

[nedbat]

👍