Some immediate use-cases in the field will require adding more categories and entities in the Cask Market. To account for these, there should either be:
1. A way to drop icons somewhere and have them show up for these new categories and entities
2. A hard-coded/default mapping for icons to use for all things that do not have an icon specified.
In fact, we should have an icon for every letter in the english alphabet. Then, if an icon is not found for an entity, use the icon that corresponds to the first letter of the entity name.