Offline usage: avoid re-downloading glfw and freetype about hello_imgui

[pthom]

Hello,

Hello ImGui will try to find glfw and freetype via find_package. If it cannot find them, it will try to download them.

I would advise you to install them for example via vcpkg once for all; Thus the download will be skipped.

[leavittx]

I was able to get it working with vcpkg following
https://github.com/microsoft/vcpkg?tab=readme-ov-file#quick-start-windows
and partly https://learn.microsoft.com/en-gb/vcpkg/get_started/get-started?pivots=shell-cmd
(the vcpkg add port <packages> command)
However I had to install lunaswg separately, otherwise the lunasvg.h header wasn't found in imgui_freetype.cpp.
Final install command for the project: vcpkg add port freetype glfw3 lunasvg