UI/UX improvements

[arl]

Frontend performance improvements:

• only render visible plots
• do not render all plots in the same frame. Stop rendering after 16ms (~60 FPS), and program rendering of the successive plots in the next frame. This prevents hanging of the main task for too long.

UI improvements:

• Alt+Click on a category to show only that category
• Add a search bar to only show the plots using a metric, or plot with a given name.