Export function for Integrated Deferment

As I user I want to have an export function for the integrated deferment panel as an Excel and to append the deferment panel to the PDF export. 

Function 1: Add Export function to deferment panel

Function 2: Add Deferment Summary to PDF Export

If a deferment panel is available for the selected plan, it should be added to the PDF Export as a summary of the selected Period at the end of the report. 

Acceptance Criteria:

• User can export the integrated deferment for the selected period on the lowest grouping level (Facility or Production Subsystem)

• When the user exports the plan as a PDF, the summary of the selected period is appended to the existing PDF Export on the last page. 

​@Marius Biermann ​@Lukas Volker as discussed in previous sessions!