Resolve 1055-pdf-export-look-and-feel-notes

Due to some weird behaviors of pdf-lib and the SVG path of the boxes, I had to resort to some hardcoded crooked numbers for clean and proper placements. I added some transparency to make the color of the background box lighter.

Please add ExampleIncomingSessionModule for testing.

Also this builds on the MR #1038 (closed) due to the usage of the headingMargin which was introduced there. Thus please make sure that #1038 (closed) is already reviewed and best case merged.

Closes #1055 (closed)