Description
The current behaviour of gremlin server when an error or exception is thrown is to serialize the full throwable and return it to the client.
Based on this discussion in the dev list, it is preferable to only return errors which might be considered useful to a user, and replace other errors with a more generic InternalServerError response.
There remains an open question of exactly which errors and exceptions should be returned in detail. Current intention is continue returning all `Exception`s which are thrown. Any `Error` will be replaced with InternalServerError unless the original error is included in a whitelist which allows it to be sent. If any `Exception` is identified which the community feels should not be returned, a blacklist of exceptions can be added as well.