feat(developer): polish Keyman Developer Server

Not worth splitting all this polish into separate commits, I think...

1. Add frames for other device types
2. Reorganise menus including burger menu
3. Highlight button after upload to show where file is accessible
4. Fix cropped device frame images, scrolling
5. Improve device menu
6. Add Keyman Developer logo and watermark
7. Add status box with current keyboard, model and device
8. Cleanup z-indexing
9. Add About dialog
10. Add Help links
11. Report version in About dialog, title on logo hover
12. Ensure keyboard reloads after change
13. Support loading models over https