[LAUNCHER] rust-utils built with vcpkg provided libsodium result in missing dependencies

[matthme]

When building the rust-utils Rust node add-on with libsodium from vcpkg, like on this branch, the node add-on ends up linking libsodium.dll dynamically and launcher correspondingly fails to start up with missing dependencies on Windows.

It has been verified with

dumpbin /DEPENDENTS [name of node addon].node

that the generated node add-on depends on libsodium.dll dynamically and it is not clear why that's the case since the logic in the build script of libsodium-sys-stable would indicate that it would be linked statically if SODIUM_LIB_DIR is provided and SODIUM_SHARED is not set (both of which had been verified to be the case by adding tracing to a fork of libsodium-sys-stable).