Uhepp data actions

Implement first set of uhepp manipulations

• Rebin
• Stack type
• Colors

changed milestone to %First release

marked the checklist item Rebin as completed

assigned to @frank

• Systematics (select of envelope, maybe multiple; morphing)

created merge request !15 (merged) to address this issue

mentioned in merge request !15 (merged)

Systematics ratio missing

closed with merge request !15 (merged)

reopened

marked the checklist item Stack type as completed

marked the checklist item Colors as completed

closed