Add POSIX mqueue implementation to the Monitor example

In our existing reference implementation, the monitor application uses a TCP/IP implementation called connection_ip.c to communicate with the rendering process. This involves using a message proxy, which converts TCP/IP events to POSIX mqueue events.

However, this indirect communication via TCP/IP and the proxy is unnecessary and complicates our system's architecture. To simplify and streamline our processes, we propose bypassing this and communicating via posix mqueue directly between the monitor and the rendering process.

The task requires implementing a new interface connection_posix in the monitor example. This class will facilitate direct communication using QSafeEvents from the monitor to the renderer, bypassing the TCP/IP and proxy.