Include `fs2.io.file.Path` into the library

[Hombre-x]

We should re import this type into shellfish as it is an essential dependency on the whole library. I don't know the best way to achieve that but it would be nice to do something like this:

package shellfish.domain

import fs2.io.file.Path as Fs2Path

type Path = Fs2Path

And in the import package:

package shellfish

export shellfish.domain.Path

export shellfish.FilesOs

export shellfish.syntax.path.*

So doing import shellfish.* would import everything including the Path type.

[TonioGela]

I'm not 100% sure that's a good idea. Magically importing too stuff would hide too much complexity to the users IMHO. Also the import of fs2.io.file.Path is the very same the users will have to do when using fs2-io directly, so there's an added value in forcing them to use it.

For what concerns the uni-import, once decided the name we'll restructure the lib and possibly put everything in the <lib-name> package, so that we can import it with import <lib-name>.*