Add ubuntu steam path to getSteamLocations

[cshingle]

Add Ubuntu Steam path to getSteamLocations

[Garethp]

Would you mind also adding this to the ScopeHelper in C# as well (located here). At some point I should try to generate some models to get the Kotlin and C# sides using the same code for this, the way that Remodder handles Kotlin/C# inter-communication, but for now the ScopeHelper exists in both parts of the code

[cshingle]

I added the change you requested.