Annotation In Cell: Allow the user to choose the color of the annotation (Stretch Goal)

### Background
The current goal is to have all annotations be rendered the same color.

We have the capability to render annotations different colors, and to save those choices as part of the annotation, so it wouldn't require much backend work. But adding colors will be a bit of an undertaking, so we're only going to do it if we've really nailed everything down already, and we have free time

### Acceptance Criteria
- A default annotation color is shown in the writing / editing dialog
- The user can choose the color the annotation being written
- The color defaults to the last chosen color if the stream exists
- The color is stored as a sticker on the annotation