For an explanation of the problem those keys was working around and a
resolution thereof, see
https://www.erp5.com/group_section/forum/Need-help-to-fix-shacache-upload-SEiYkNyXWq/view?list_start=8&reset=1#2061505002

Use slapos key and certificate instead of Wendelin user and password.
Use get computer_id for Wendelin reference in ```/etc/opt/slapos/slapos.cfg```.