Model.validate() should allow server side data to be returned

[tohagan]

Feature request. A failing validation from Model.validate() currently only returns the validation code. however in some cases a code property may be inadequate as in order to the build the localised error message client side, you may need to additional server side data from other records or server side logic so ideally, the code could become an error object containing the code + other data. See #255 discussion.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been closed due to continued inactivity. Thank you for your understanding. If you believe this to be in error, please contact one of the code owners, listed in the CODEOWNERS file at the top-level of this repository.