Make usage of React and GraphQL clearer

Created by: felixfbecker

We get a decent number of candidates that claim they didn't finish because they had to spend significant time at the beginning getting their way around in GraphQL and React because they had never used it before, or only a long time ago. We don't require any advanced features, only basics that should map quite well from other frameworks and technologies (which are a qualification requirement to know). So just a little "brushing up" is enough, but when that takes time from the exercise, it's still costly and can present a significant disadvantage I want to avoid.

This does add a bit more time investment for these candidates, but the reality was that this was already "required" before because it was hard to succeed without. I think this is okay because we really only require "take a look at a hello world example"-level basics and it's not "wasted" time (they'll learn something useful). There was also precedent in the previous TypeScript exercise for this kind of suggestion.

I also bolded the technologies, because apparently some candidates read over them.