Add support for sending a file to the remote server.
Add support for sending a file to the remote server.

This patch also refactors WinRemoteClient, by adding
private support for running multiple commands over the
same shell id.

cmin764/argus-ci,micumatei/cloudbase-init-ci,cloudbase/cloudbase-init-ci,AlexandruTudose/cloudbase-init-ci,PCManticore/argus-ci,stefan-caraiman/cloudbase-init-ci