PCB Editor: Separate Grid Origin color setting

Description

It's more of a wish than a bug.

When the grid in the PCB editor is set to lines, and the grid color does not have much contrast to the background, the Grid Origin is hardly visible. It would be nice to be able to set the Grid Origin color separately from the grid color. Or distinguish the Origin Grid in some other way, (for example, thickness) so that it is not a big intervention in the code. So that it can be released in version 7 :-)

Steps to reproduce

KiCad Version

Application: KiCad x64 on x64

Version: (7.0.0-rc1-145-gbd6d0b6cb6), release build

Libraries:
	wxWidgets 3.2.1
	FreeType 2.12.1
	HarfBuzz 5.0.1
	FontConfig 2.14.1

Platform: Windows 10 (build 19045), 64-bit edition, 64 bit, Little endian, wxMSW

	wxWidgets: 3.2.1 (wchar_t,wx containers)
	Boost: 1.80.0
	OCC: 7.6.2
	Curl: 7.86.0-DEV
	ngspice: 38
	Compiler: Visual C++ 1934 without C++ ABI

Build settings:
	KICAD_SPICE=ON