No need to install. It is still there with just the shortcut removed. To start it, goto your contacts and tap on the address of one of your contacts. This will start Bing Maps.
Like the other reply said, Bing Maps is still available but there's no official way to get the shortcut back.
I wrote a free app that just opens Bing Maps. You can find it in the store under the name FastMaps or you can go to the site http://www.windowsphone.com/en-us/store/app/fastma
It was just published to the store today but I already submitted a bug fix; there was a problem with the location detection. It still opens Bing Maps but the option to open to your current location is broken without the update, which should go through quickly.
Thanks and enjoy!