UX Milestone process for Knowledge

Knowledge is a unique space in GitLab with lots of room to grow. Based on previous conversations, we want to do UX work 1 milestone ahead of doing actual build work. Let's define a clear process of how we can determine designs based on research, user testing, etc. before moving forward with a build. The outcome of this milestone should be whether or not we build something, saving time in building something that our users might not find useful.

Katherine mentioned levels of confidence. If we are more confident in something, we could go straight into solution validation versus if we have a low level of confidence, we do a different type of research.

cc @katokpara