[WIP] Multigame Support

[StollD]

I decided to start working on this, since @V1TA5 named it as a requirement at some point, and I think we should start working on it.

My work as of now was, to replace the gameshort references to the settings file with url parameters or values fetched from the mod itself. At some points this was rather easy and smooth, at others it is a bit hacky and ugly.

There are some more or less breaking changes: The browse routes require the gameshort to be added in front of them now, same for the random mod and mod creation routes.

Generally, I would like to break compatibility with the current routes and add the gameshort in front of every game specific route, even mods and mod creation. The reason is, that it is much easier to have the game supplied by the URL than to add a selection to, lets say, the mod creation dialog. And I think it adds some kind of consistency.

But of course I know that we cannot simply break all mod links that are on the forums and so on. I suggest, that we still add the old mod route, but don't have any templating behind it. Instead, the PHP should query the backend (specifically the /api/adapter/mod/ route), and return a redirect to the URL with the matching gameshort.

Currently this is broken at some point, but I will fix this as soon as I got time