Fix weighting bugs

Sum of weights does not yield one per service for DESY Rancher and DESY S&S (as it should) after last changes made in !96 (merged) and !98 (merged).

• https://codebase.helmholtz.cloud/hifis/overall/kpi/kpi-plots-ci/-/jobs/1430311/artifacts/file/results/kpi_per_service.csv ❌

So, kpi-weights needs to be corrected.

Obviously there were too many manual (mis-) calculations in:

• Usage already sums up to 1 (not including users), introduced in !96 (88090db8)
• Comma error introduced in !98 (9e87e4c8)