Backport the simple chat example. The application implements a simple
messenger using Qt GRPC. It shows how to utilize the server-side
streaming and use the call-based user/password credentials.
Task-number: QTBUG-109598
Pick-to: 6.5
Change-Id: I4ca3695780a9cc9991c92c4423e3af9d8e0eaf35
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Alexey Edelev