Experiment BT support using Chrome web serial (#920)

* plumbing

* plumbing

* logging

* more notes

* fixing typing

* more plumbing

* more plumbing

* different baud rate

* talking to the brick

* first over the air drop

* fix buffer

* tweak paraetmers

* formatting fixing double upload

* reduce console.log

* cleanup

* add BLE button to download dialog

* changed label

* recover from broken COM port

* fix function call

* reduce log level

* adding ticks

* some help

* updated support matrix

* more docs

* updated browser help

* more docs

* add link

* add device

* added image

docs/about.md

@@ -28,7 +28,7 @@ program to a **.uf2** file, which you then copy to the **@drivename@** drive. Th
 
 ### ~ hint
 
-Not seeing the **@drivename@** drive? Make sure to upgrade your firmware at https://ev3manager.education.lego.com/. Try these [troubleshooting](/troubleshoot) tips if you still have trouble getting the drive to appear.
+**Experimental support** for Bluetooth download is now available. Please read the [Bluetooth](/bluetooth) page for more information.
 
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