Image similarity (frontend)

Branch: `image-similarity-frontend`

### Task at Hand
- [ ] Implement two basic HTML buttons with no styling. The first button allows a user to upload a full-color image. The second button allows a user to upload a sketch that they drew of the original image. When both files are uploaded, a third button is enabled which when clicked, converts the original image into a sketch using our ML pipeline and then does image similarity with the user sketch. A single integer is displayed as the similarity score.