Add an initial Linux implementation of a VirtualizationInstance
with the same types, callbacks, and functions as the Mac interface.

The underlying dynamic library used by the interoperability layer
is not included here due to anticipated licensing requirements,
but would be provided separately.

Note that it may be valuable to consider a future refactoring of
identical classes between the Linux and Mac implementations (such
as PrjFSLib.Linux.Result and PrjFSLib.Mac.Result).