Feature-request : add ability to drag-and-drop files handled to editors.

Description

KICAD should support drag-and-drop files operations :

• Gerber files handled to either the Gerber Viewer editor window or the project manager window ;
• All other file types handled in the associated standalone editor window.

Steps to reproduce

D&D files operations are not supported.

KiCad Version

Application: KiCad

Version: (6.99.0-1871-gc8978836f0-dirty), release build

Libraries:
	wxWidgets 3.1.5
	FreeType 2.12.0
	HarfBuzz 2.7.4
	FontConfig 2.13.1
	libcurl/7.83.0 OpenSSL/1.1.1o zlib/1.2.11 brotli/1.0.9 zstd/1.5.2 libidn2/2.3.2 libpsl/0.21.0 (+libidn2/2.3.0) libssh2/1.10.0 nghttp2/1.47.0 librtmp/2.3 OpenLDAP/2.5.11

Platform: Linux 5.17.0-1-amd64 x86_64, 64 bit, Little endian, wxGTK, gnome, wayland

Build Info:
	Date: May 11 2022 23:28:13
	wxWidgets: 3.1.5 (wchar_t,wx containers) GTK+ 3.24
	Boost: 1.74.0
	OCC: 7.5.1
	Curl: 7.83.0
	Compiler: GCC 11.3.0 with C++ ABI 1016

Build settings:
	KICAD_USE_OCC=ON
	KICAD_USE_EGL=ON
	KICAD_SPICE=OFF