exporter.exe should create valid Windows images

[natalieparellano]

Description

exporter.exe as it compiles currently does not create valid Windows images.

Proposed solution

exporter.exe should create valid Windows images.

Describe alternatives you've considered

Additional context

• Currently, layer tar files are written with paths starting from e.g., /cnb - this should be Files/cnb on Windows
• The output image manifest should be valid for Windows

Acceptance criteria

• When exporter.exe is invoked with the right arguments (e.g., when called by a platform such as pack)
• docker run <output-image> succeeds