Enforce semantics on HoodieRecordPayload to allow for a consistent instantiation of custom payloads via reflection

At the moment, the expectation is that any implementation of HoodieRecordPayload needs to have a constructor with Optional. But this is not enforced in the HoodieRecordPayload interface. We require a method to enforce a semantic that works consistently.

## JIRA info

- Link: https://issues.apache.org/jira/browse/HUDI-93
- Type: New Feature

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## Comments

29/Dec/19 14:29;Pratyaksh;[~xleesf] Are you still working on this? Can I take it up? ;;;

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31/Dec/19 12:15;xleesf;[~Pratyaksh] Feel free to grab this ticket since I am a little busy recently. And assigned to you.;;;

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13/Mar/20 10:11;Pratyaksh;[~xleesf] [~nishith29] How do we plan to go ahead with this? Any thoughts on how can we enforce the semantic? ;;;

Start with the HoodieRecordPayload interface and the existing custom-payload reflection path described in the issue. Determine how the Optional constructor expectation should be enforced, then verify that custom payloads can be instantiated consistently through reflection.

Written by the indexing model from the issue text.