Integrated fps counter

[glaere]

It would be great if GameHub could integrate an fps counter. Steam is a partial workaround for this but it would be good if an fps counter could be used for GOG/other games as well as wine games which I currently don't know how to get working with the Steam fps counter.

[tkashkin]

We can integrate MangoHud as a tweak.

Install MangoHud and save this tweak into any of tweaks directories (listed in Settings).

{
	"id": "mangohud",
	"name": "MangoHud",
	"description": "A modification of the Mesa Vulkan overlay. Including GUI improvements, temperature reporting, and logging capabilities",
	"url": "https://github.com/flightlessmango/MangoHud",
	"command": "mangohud ${command}"
}