UTC option

Add the option to specify the time in UTC instead of local time. It can be used to specify an absolute time which is not impacted by daylight saving changes throughout the year.
This is an advanced option that should not be used in the majority of the use cases. It should be used only if there is a very concrete reason to do so. The default for the UTC option is false and it's backward compatible, so no action is needed unless you want to use this feature.