Removes the "Export As CSV" and "Export As PDF" options from MotionList
view and adds an export dialog instead (just like OS 2.3)
The exprt Dialog dynamically changes it's content according to the possible
selections.
The current implementation of the CSV exporter is not able to export anything
but the original motion text. The exporter does consider this and disables
this option for now.
While the old exporter showed "state" and "recommendation" during CSV export,
but was in fact not exporting state nor recommendation, the new exporter
will disable these fields during CSV export.
PDF should work as expected
Ports the "Motion Catalog Content Provider" to OpenSlides 3.
Categories and Prefixes are considered as before.
Updated to Code to ES6/Typescript.
Allows to export all motions from the motion list view.
