The motivation for this setting is that the current default of 1.0 is often too large. When many collection instances are created, all lines in the viewport create a mess.
This adds a new preference setting in `Editing -> Objects -> New Objects`.
By default, it's set to 1.0, which matches the current behavior.
This was requested by @sebastian_k.
{F8518494}
Maybe someone has an idea for a better/shorter name?
I'm not absolutely sure if I have to add versioning code for this, or if adding the setting to `U_default` is enough.