Deprecated support for older dependencies in VS Community

[kieranmillar]

curl-7.27.0 and expat-2.1.0 can no longer be built in freely-available versions of Visual Studio Community. At least, not in the way the python script tries to by upgrading the dsw file into a sln.

https://learn.microsoft.com/en-us/cpp/porting/features-deprecated-in-visual-studio?view=msvc-170#deprecated-in-visual-studio-2022

Both of these dependencies have a CMAKE available so there might still be a way. For me, as a workaround I copied the previously-built dependencies from my old computer over to my new one.

An alternative solution to fixing this directly might be to save somewhere the outputs we move into the Deps folder, if not in this repo itself, then perhaps somewhere else. Maybe I could spin off my own repo and host it. This would save anyone from having to build the dependencies themselves at all.