Integrate all tests into a single executable

As previous commit but applied to `flightvars` project.
Split mqtt/broker.h into smaller units

A new unit mqtt/broker_mosquitto.h appears after this change. Any
further `broker_runner` implementation would be in a separate unit.
Add some util functions to use WIN32 API

WIN32 API functions use to return integer values indicating whether
the things are OK and, otherwise, a `GetLastError()` function is
provided to check what's the exact cause of the problem. While coding
in C++, a terrible pattern is repeated again and again: invoke the
function, check the result, if failure invoke `GetLastError()` and
then throw the exception.

This change provides a util header `liboac/util/win.h` that provides
utility functions and macros to invoke WIN32 API functions that
converts their error codes into an exception.
Replace Mosquitto service runner by none in config

Having a Mosquitto Windows service MQTT broker runner is not trivial.
On Windows platforms, a process must have special privileges to
manage system services (makes sense after all). Therefore, it is not
possible that FlightVars plugin manages the state of Mosquitto broker
service.

New approach: after Mosquitto installation, the broker service is
installed and configured to be started on each reboot. So there
should be a running broker on any windows box with Mosquitto installed.
That means... no need for a runner!

This change removes the `MOSQUITTO_SERVICE` from the
`mqtt_broker_runner_id` enum and provides a new default one: `NONE`.
Improve FV module logging and error reporting

With this change, in case of invalid config file an error is reported
in a popup Window rather than silently failing. Some log messages
have been improved as well.