[GS] add a control panel for gama-server in GUI mode

[lesquoyb]

Is your request related to a problem? Please describe. Now that gama-server in GUI is well-established, it would be nice to be able to control it more precisely, for example with a dedicated control panel. I think that would greatly help everybody working on clients for gama-server whether they are developing something or just users, and it would also probably help gama developers too for debugging purposes.

Information and controls that I would find interesting are:

• current state (running or not, is there an exception like port already in use ?)
• current port
• connected clients (just a number, or better with the details of ip addresses for example)
• a real time view of raised exceptions (if any)
• a log of raised exceptions
• a real time view of client requests
• a log of received requests ?
• stop/start the server
• change port
• activate at startup of gama or not

Btw I'm piggy backing a minor issue with this one: I think we could also change the default value for activating gama-server at gama startup. Currently it's true by default but the number of people actually using it is pretty low and they are all advanced users. In addition, having it set to true by default would make the OS ask you for permission to use the network on the first start of gama, which would seem weird for most users.

Describe the improvement you'd like The creation of a control panel as described above accessible from the gama user interface

[lesquoyb]

I was thinking lately that it may be a good idea to have this information available through gama-server itself through commands or something similar. This way we can build this panel inside gama, but we can also build other personalized control panels on top of gama-server headless. I was thinking maybe an admin page for a future gama-headless server docker image. Anyway, if it's the case we should probably only allow those commands for "admins" and the way I propose we handle it is to open a dedicated port for admin connection, this way gama doesn't have to integrated authentication itself as it would be something that's managed by the local user/sysadmin. What are your thoughts ? @RoiArthurB maybe you are the most knowledgeable in that area ?