Add Cumulative Update Dropdown (OOB and Preview Options) to OSDCloudGUI

Currently I am scripting my own CU update after OSDCloudGUI runs. We have found not applying recent CU's will cause User Driven Enrollment to fail during Autopilot. It would be nice to be able to have OSDCloud pull the current CU for the image that is selected and apply that after the OS is applied to the device. It would be one less step i need to script for. Having a variable in the osd-amd64.json to specify a KB would be a nice touch as well.

Here is my script for reference: https://github.com/Justin-Swets/OSD/blob/main/AutoCU-Update.ps1