Feature: Highlight comics that match certain conditions

[ijprest]

It would be nice to highlight comics that match various conditions, e.g.:

• highlight owned / wanted / sold comics
• highlight untracked issues
• highlight issues with missing cover images
• etc.

[ijprest]

Now highlighting untracked (red), wanted (blue), ordered (green), sold (light-gray foreground), for-sale (red foreground).

• Still not tracking/highlighting missing covers.
• Would be nice if the colors were user-configurable.