All errors should translate to appropriate API-level HTTP statuses

[mortent]

All errors in porch should be handled correctly in the apiserver and return the appropriate k8s errors. They should also include sufficient information to be useful and actionable. Currently Porch doesn't always handle errors correctly, leading to errors being logged from the aggregated apiserver and the user getting a generic error.

[yuwenma]

@mortent Do you mind giving some guidance or examples about this issue? Otherwise I feel like it might be too challenging for new contributors to understand and work on.

[yuwenma]

Bump the priority because this issue can really improve the user understanding of Porch