Add requisite dependencies for building crates on Windows

[ecstatic-morse]

This is meant to be an ongoing tracking issue. If anyone observes a crate failing to build due to a missing dependency, post it here.

Libraries should be added to vc-packages.txt and will be automatically installed via vcpkg. Executables should be installed via choco-packages.txt.

• freetype (required by jjjjw.rust_elmish_rocket)
• pkgconfig (required by curl-sys)
• libgit2
• libmysql (mysqlclient required by astaupb.wp_posts_api)
• libsndfile
• libusb (required by libusb-sys)
• opencl (required by ocl)
• portaudio (required by weresocool-0.1.0)
• SDL2-image (required by ruscur.phase)
• python (3, named python.exe) (required by shaderc-sys)
• clang (required by wepoll-sys-1.0.3)
• curl
• cmake (required by shaderc-sys)
• libsodium
• libssh2
• libpq
• ninja (required by shaderc-sys)
• openal (required by Tethik.beepr)
• openssl (required by rust-openssl)
• portmidi (required by diaschisma.mimi)
• sdl2 (required by Ade-AWD.Foxxy)
• sqlite3

[ecstatic-morse]

I found some candidates by looking at the reverse dependencies of vcpkg.