[C++] Addition of a server for Qt5

[etherealjoy]

I have been using the generated models from the Qt5 Client for integration with this qhttp server

With Qt6 on the radar coming with integrated server functionality does it makes sense to have a server at this moment?

@MartinDelille @stkrwork @ravinikam

[stkrwork]

There is the option to do both, one with QT6 and one with QHttp. Then a developer can choose between the two. Another C++ Server could be useful, so Users can have another option besides Restbed and Pistache.

[MartinDelille]

Personally I use Qt only for the client.

[etherealjoy]

@stkrwork
I think qhttp server would be a good candidate

We can reuse all client templates from cpp-qt5 for the models
Main thing is to wire the request via a router to the model and handling the callback to how pistache is doing.
But from what I see Qt5 with qhttp can do it more eloquently.
what do you think?

I am really looking forward to Qt6 integrated HTTP server

cc @MartinDelille
cc @ravinikam

[etherealjoy]

Another option would be qhttpengine

[etherealjoy]

I just read on phoronix that Qt6 is far away, I think we could just give one of these http engines a try.
Qt5 will go all the way to 5.14 so we are far off from Qt6

[etherealjoy]

Integrated with #322