Add --network-mode option to activate mounting as network drive without having to set volume prefix.
Add support for automatic drive letter assignment (not specific to network drive mounting).
Allow full network share unc path in --volname, which will also implicitely activate network drive mounting.
Allow full network share unc path as mountpoint, which will also implicitely activate network drive mounting, and the specified path will be used as volume prefix and the remote will be mounted on an automatically assigned drive letter instead.
