Provide more info about api failures

[jvalkeal]

For example when doing task create/destroy/launch for task which doesn't exist, server and extension logs:

16:34:25 - Info - Creating task task1
16:34:25 - Info - Task task1 create failed
16:34:26 - Info - Destroying task task1
16:34:26 - Info - Task task1 destroy failed
16:34:27 - Info - Launching task task1
16:34:27 - Info - Task task1 launch failed

vs

dataflow-server_1  | 2020-05-16 15:34:25.886  WARN 1 --- [nio-9393-exec-2] o.s.c.d.s.c.RestControllerAdvice         : Caught exception while handling a request: The 'task:timestamp' application could not be found.
dataflow-server_1  | 2020-05-16 15:34:26.867  WARN 1 --- [nio-9393-exec-2] o.s.c.d.s.c.RestControllerAdvice         : Caught exception while handling a request: Could not find task definition named task1
dataflow-server_1  | 2020-05-16 15:34:27.915  WARN 1 --- [nio-9393-exec-5] o.s.c.d.s.c.RestControllerAdvice         : Caught exception while handling a request: Could not find task definition named task1

Would be nice to show proper error to user.