Parameter handlers

[cicdw]

Thanks for contributing to Prefect!

Please describe your work and make sure your PR:

• adds new tests (if appropriate)
• updates CHANGELOG.md (if appropriate)
• updates docstrings for any new functions or function arguments, including docs/outline.toml for API reference docs (if appropriate)

What does this PR change?

Fixes a bug in handle_inputs where result handlers weren't stored. Adds JSONResultHandler to all Parameters for when they need caching

Why is this PR important?

Just ensures that whenever Parameters are cached as inputs, they go directly to the DB for simplicity and a better user experience