Quick and horribly dirty fix for dissapearing comment/location

Comment and location are disappearing when the user joins the queue, which makes QWait almost unusable at lab sessions. https://github.com/mvk13ogb/qwait/issues/165

The theory is that as we call the API with both location and comment straight after each other, there is a concurrency issue in the database and they overwrite eachother. This would attempt to solve it by after setting the location waiting 500ms before setting the comment, which could fix the problem (but I don't know due to https://github.com/mvk13ogb/qwait/issues/168)

This code objectively sucks, and the best that I can say about it is that it compiles. There are lots of better ways to fix this and I would gladly take any of them so this PR can be closed and forgotten, but at this point an ugly fix is better than no fix.