Feature Request: Branch Comparison Mode

[mattangus]

I currently manage different models (for example small, medium and large). The way that I do this is by having a branch for each model type. Since these models serve different purposes (accuracy/runtime tradeoff) I need to maintain top performing models for each of these types. It would be great to have a mode where DVC studio only displays the HEAD of each branch to get a quick comparison accross different branches. This differs from the current view that displays the last 3 commits from each branch. Ideally this would also be a toggleable viewing mode.