Cloud KPI: add explanation about T_fitstart, T_reference

For all who do not understand the mathematical explanation, we need to add a text regarding

• T_onboard

• T_logstart

• T_fitstart

• T_fitstart, manually defined

• T_reference_overall

• Startwert ist fix und ändert sich nicht

• der Startwert kann nicht unter dem 1. echten Meßwert liegen

  • er kann aber höher liegen

changed due date to February 15, 2024

assigned to @SpickerHZB

changed title from Cloud KPI: add explanation about T_fitstart to Cloud KPI: add explanation about T_fitstart, T_reference

created branch 98-cloud-kpi-add-explanation-about-t_fitstart to address this issue

mentioned in merge request !526 (merged)

closed with merge request !526 (merged)

mentioned in commit 7f805980