* Add `InputElementValue` as type when needed

Since no default size is set, the default font size is set to 16px, 
which is the browser(?) default on my PC.

Margin between lines and between button and it's label.

Before it was done with a dysfunctional hack. Now with proper extensions 
to existing (tiptap-node-)extensions.
Also reads existing style and sets select-element accordingly.

Use proper types and remove unused vars.

No longer is async. For elements which need upfront source info (media), 
the media prompf is done in the unit service. Here we can keep it 
simple.
Also remove coordinates from factory as this is information that does 
not need to be known here. This is also handled in the unit service 
where applicable.

Remoove unnecessary type casting, unused variables and consoles
statements.

Was using the wrong value for determining what page to delete from. Now 
correctly uses the SelectionService.

Colors and font stuff.

Update npm version info

Now uses tabs and improved order or inputs.

To make it's purpose clearer.

All values returned are set. This way there are less useless calls.

The labels are still the internal names. Needs to be fixed next.

Should at least be in util folder. And since it is imilar functionality 
to the unit factory it is placed within.

Less intrusive colors and border style.