Problem Description:

in many places, the rest api checks for a ProcessEngineException and then returns a 404 response (or 500)

This is undesirable if the ProcessEngineException is actually an AuthorizationException since in that case we want to return 403. (see: http://docs.camunda.org/7.2/api-references/rest/#overview-introduction-authorization-exceptions)

Note: this needs to be fixed before the 7.3 release since fixing it after would not be backwards compatible