Hi @langfr,
there is not Out-Of-The-Box solution. The engine has plugin point to register your own BusinessCalendar. Have a look at the package https://github.com/camunda/camunda-bpm-platform/tree/master/engine/src/main/java/org/camunda/bpm/engine/impl/calendar.
The dafault calendars are registered in the ProcessEngineConfigurationImpl: https://github.com/camunda/camunda-bpm-platform/blob/2bd5b44213e3637fe12797591837b9a1afdc8feb/engine/src/main/java/org/camunda/bpm/engine/impl/cfg/ProcessEngineConfigurationImpl.java#L2103-L2112
You could register your own business calender in a process engine plugin.
Hope this helps,
Ingo