Mod Menu Tweaks

[Tisaku]

A restructure of the MODS menu.
-Create a button to quit Factorio without restarting - because sometimes you just want to get rid of that mod and call it a day.
-change behavior of update mods button to update the mods without restarting - I have to choose between updating or getting new mods why?
-change behavior of install mod page to return to mods page without restarting - I have to choose between getting new mods or updating why?

Basically a few (possibly) simple tweaks that make fiddling around with mods quicker and less irritating.