pwa-chrome is the new thing that came in with more recent versions of Visual Studio Code. It enables the "targetSelection" setting, which lets you pick which thing to debug instead of debugging every Aardvark gadget.
* Replaced window.open with a blank window and the populated that with an ImageAdder react component.
* Switched the image list to be part of ImageMenu's state so it can be dynamic.
* Added a little form to that component that lets the user enter a URL. When they hit "submit", add that to the image menu.
