Schema registry: add json support

[jnoynaert]

Who is this for and what problem do they have today?

For engineering teams not familiar with Kafka, the easiest onramp to publishing to Redpanda is json serialization (no additional dependencies or overhead of learning a binary format) published via http proxy (no need for a Kafka client library and the associated patterns for publishing).

Doing with this Redpanda today means forgoing use of schema registry for those topics, even though many Kafka implementations rely on schema registry as part of the overall workflow for governance, discoverability, etc.

What are the success criteria?

Users can successfully register json schemas with Redpanda schema registry.

Why is solving this problem impactful?

Opens up use of Redpanda to more teams while maintaining governance and usability benefits of schema registry

Additional notes

Original slack thread

JIRA Link: CORE-1011

[vblackburn]

+1

[alexisread]

+1

[ffernandolima]

+1

[toannhu96]

+1

[thonipintu]

We need it!

[matutter]

Are there any comments from the devs or idea of where this stands on any kind of roadmap?