There are around ~400 icons in the `assets/icons` folder, but in reality
including file icons we only use around 50. In a number of places we use
different variants of the same icon, even in different styles.
This PR unifies the icons we use, removes the duplicates, and cleans out
unused icons.
Release Notes:
- Made icons more consistent throughout the app.
Nate Butler
4c9100eae3