Move `Steps` setting from `Preferences` to `Document Properties`

Migrated from https://bugs.launchpad.net/inkscape/+bug/1707823
From 2017-08-01

Original title: Make ‘Steps’ setting per-document

Summary (edited):

onixar wrote...

...the Preferences > Behavior > Steps > Arrow keys move by and Inset/outset by are set in the global preferences. This is very inconvenient. While the Arrow keys move by value of, say, 1 px is fine for documents with pixels as the main unit, it becomes completely useless for millimeter or inch documents. I have to check the Steps values every time I open a document and set the units accordingly. It’s a pain.

Is it possible to move the Steps settings to the Document Properties?

Version Info:

- Inkscape Version: n/a
- Operating System: n/a
- Operating System version: n/a