disable main-window scrollbars to get more editor workspace

Description

proposal / for discussion:

On working with CAD-programs it's important to have a big real estate working area in the main editor windows. This is more important if the gui gets more and more functions added over time (navigator panel open at eeschema, the future property inspector, the appaerance manager in pcbnew). As useful as these additional menus/functions are they eating up working space.

Some small action could be to enable a turn-off of the main-editor-window-scrollbars, though I don't know how strong this impacts the gui-code (and so how hard it is to implement).

Background: I have taken this idea from Circuitstudio. On observing my own workflow with kicad I can state:

• If working with a wheel-mouse (on my office-desktop-system) the scrollbars are not used. All zooming/scrolling/panning is done with mouse-movement/mouse-wheel. I would not miss the scroll-bars at this point and happily exchange them for more work-space.
• If working with the built-in trackpad of the laptop the emulated scroll-wheel-action doesn't work well (on my laptop), so there the scrollbars are still necessary.
• So there could be an option on kicad->preferences to turn-on/turn-off the main scrollbars at user-wish.

Steps to reproduce

1. look at the attached picture of the current gui-design. It shows the scrollbars of kicad as opposite to circuitstudio

KiCad Version

Application: KiCad Schematic Editor (64-bit)

Version: (5.99.0-12108-ga1521d338e), release build

Libraries:
	wxWidgets 3.1.5

Platform: Windows 10 (build 19041), 64-bit edition, 64 bit, Little endian, wxMSW

	wxWidgets: 3.1.5 (wchar_t,STL containers)
	Boost: 1.76.0
	OCC: 7.5.0
	Curl: 7.74.0-DEV
	ngspice: 34
	Compiler: Visual C++ 1929 without C++ ABI

Build settings:
	KICAD_USE_OCC=ON
	KICAD_SPICE=ON