Update handling of "Unused Sets"

[alexsb]

For this here:

• Remove the Sort Sets Button
• Add a vertical label called "Unused Sets" (should look like the sets label described in #110)
• Add the sort functionality to the context menu for the label

[JakeWags]

@alexsb Could you clarify the styling for the "Unused Sets" label? Do you still want to display all the unused sets?

[alexsb]

Here's a design:

https://www.figma.com/file/O031Jl2qjDIyCfb66Z01Qp/UpSet-Set-Menu?node-id=0%3A1&t=Jgx1ssgBBLIIBVnj-0

Notes:

• The active set bars are darker and have the label seprately
• The active set bars show the size in the bar, with a smaller non-bold font.
• The set bar font color adapts to the background
• The inactive set bar font is not bold
• All labels use proper ellipsis to truncate the label
• A tool-tip is provided for all bars
• Elements can be added or removed via context menu