Prompt “update firmware” when new firmware is available

[pschuster]

This could remove requirement of using the cloud firmware update page— which is difficult to use and confusing. That page could be used as a last ditch effort btw

[pschuster]

This should already work. We should examine why the current implementation does not work.

ESP loads the firmware.json file and sets firmware application info in local data structure. Later on it examines the firmware and compares to current settings once MK20 responded on the ping signal with current firmware version number.

Please have a look to this code:

Printrhub/esp/src/application.cpp

Line 249 in 808b6a5

_mk20->showUpdateFirmwareNotification();