Allow users to add reference materials

[naglepuff]

Vetting Workflow

Fix #287

Models vetting details for a particular user. Right now this means being able to capture any reference materials used by a user.

This is currently implemented as a text field that is accessible from the spectrogram sidebar.

As a user types in the box, a request is made (debounced every 500ms) to update the backend with the new value. This is stored in a new database table that connects a user to their reviewer materials.