Made Distro.Name private and implemented a constructor and a getter

[EduardGomezEscandell]

Renaming a distro makes no sense, since the distro's name is the obnly parameter that is used to identify it.

To properly rename a distro one has two options:

• Export it, unregister it, and re-import it under a different name.
• Change its name in the registry (applications require elevated privilegesto do so).

Neither of these is in the current scope of GoWSL

[didrocks]

Easy change, better for third party consumer as it’s now clear what is read only. Thanks!