Currently developer needs to add a custom service or fiddle with our internal parameter. We should have a way of doing it using configuration to prevent potential issues with formula merging.

LGTM, but we will need to add instructions on how to add your own formulas for conversions.

Current options are adding entries to ibexa.measurement.value.converter.formulas service parameter (cumbersome, has to take care not overwrite values) or add your own service based on one of:

• Ibexa\Measurement\UnitConverter\AbstractFormulaUnitConverter
• Ibexa\Measurement\UnitConverter\RangeValueFormulaUnitConverter
• Ibexa\Measurement\UnitConverter\SimpleValueFormulaUnitConverter
  and tagged with a tag: ibexa.measurement.value.converter.

Introduced in https://github.com/ibexa/measurement/pull/59/files#diff-841f8421c313d9240d918fe3cb927bc683fe9a04bee0ba7765d463bda4d7a3fcR1-R151 (for reference).

We probably want to properly provide an extension point, so developers don't need to fiddle with formulas parameter.