Do small upgrades to sbt and sbt libs

[misaugstad]

Brief description of problem/feature

As opposed to #1258 which is about doing major upgrades to the libraries we use on the back-end, this issue is about making the small upgrades. For example, we are using sbt version 0.13.6, but we should be able to get as high as 0.13.17 without a problem (without needing to go to version 1.1). Similarly, we are using version 2.3.8 of the Play Framework, but we should be able to get up to 2.3.10 without needing to go up to 2.4.x. We should be able to do similar small upgrades to the libraries listed out in build.sbt.

I don't expect this to have a huge impact. But there should be some security fixes in those upgrades at least. And definitely some minor performance improvements. Maybe we get lucky and there's a new feature we can use :) I think that the upgrades to sbt might result in a faster compilation process, which would be great for development!