Compress-PSResource should output a FileInfo object

### Summary of the new feature / enhancement

By default, this command doesn't write any output to the pipeline. When you use the **PassThru** parameter, it returns full path of the `.nupkg` as a string. This should be a **FileInfo** object like most other commands return.

### Proposed technical implementation details (optional)

Be sure to set the `[OutputType()]` attribute on the cmdlet.