Open Badges 3.0: Support for external credential sharing

[e0d]

Version 3.0 of the Open Badges specification is expected to be approved in the June of 2022. This specification will allow learner to share their accomplishments across numerous networks, supporting many learner-centric use cases like:

• simplified application for degree and non-degree programs
• simplified application for employment where verification of credentials is required
• management of continuing educational units required for maintaining professional certification.

Additionally, support for Open Badges 3.0 will allow the Open edX platform to share credentials with the DCC/W3C network described in #1731 . Thus this issue is a prerequisite for that item and will represent most or all of the scope of that issue.

The specification for Open Badges 3.0 is available here: https://github.com/IMSGlobal/openbadges-specification/tree/develop/ob_v3p0

[github-actions]

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