Build failing on Windows

[milen-denev]

Reason: The reason this occurs is because in the build.rs script the developers of libsql have put the Linux cp command for copying.

Fix: I created my own copycat of cp, rust_cp. The repository has compiled binary, put this in any location you want on your windows system, and add Path environment variable, restart the system, and it should work.

[milen-denev]

#1657 libsql-ffi build failed on Windows