Enhancement: unit settings only manual changes and not entire units table

[js3110]

Description

For better implementation of the settings file in yaml form, and the R script implementation, it would be good to only track the manual unit changes (aka if conversion factor is not 1) and store those, so then the units are generated automatically and conversions are applied afterwards

Definition of Done

The requirements for the feature to be complete:

• unit changes (conversion factor != 1) are tracked and stored
• Manual unit changes stored in settings
• Manual unit changes stored in R script
• Unit changes applied to default units table after generation