Blender Git Loki

Merge branch 'blender2.8' into userpref_redesign

Go back to old size of UserPref/Settings window

If we split up and reorganize sections a bit, the current window size should be
totally fine. Bringing it back for now.

Reverts rB93edc452920870b.

Merge branch 'blender2.8' into userpref_redesign

Split up System section into General, Drawing and Devices

Initial grouping/categorizing of settings sections

Made this to work just like we define categories in menus: a enum item with only
the UI-name set starts a new category with given name. Also added another
uiLayout.prop option "group", not sure if thats such a nice way to do it though.
Will check during review.

Add placeholder sections for workspaces

Adds
* "Worspace Configuration File",
* "Worspace Add-on Overrides",
* "Worspace Key-map Overrides"
sections to the Blender settings.

Rename "Editing" section to "General"

Also moved to be first item.

Rename "User Preferences" to "Settings" in the UI

UI: Move User-Preferences navigation tabs to a sidebar region

This is the first commit for a bigger User-Preferences redesign, see T54115.

UI: Increase default size of User-Preferences window

Increased it by factor 1.28 (so we get a width of 1024px).
WM_window_open_temp will ensure the window fits into the screen, so didn't need to ensure that.