Copy `.pdb` files to `target` directory

Copy `.pdb` files to `target` directory

`.pdb` files are for windows debug info (unlike on linux, debug info is
in a separate file). Windows executable actually hard-code paths to
`.pdb` files, so debugging mvsc rust programs works even without this
patch. However, if you want to distribute the executable to other
machines, you'd better distribute both `foo.exe` and `foo.pdb`, because
absolute paths won't work on another machine. Having same-named .pdb
file alongside the binary would work though.

closes #4960