Renaming of Packages and Namespaces

[KrzysFR]

Most of the "Core" packages live in the "Doxense." namespace, and they will need to be moved to the "SnowBank." namespace.

This change would impact:

• All using Doxense.X.Y.Z; would need to change into using SnowBank.X.Y.Z;
• The various Doxense.X.Y.Z assemblies would be renamed to SnowBank.X.Y.Z.dll
• Most of the main FoundationDB client itself lives in the FoundationDB.Client namespace, so it would not be affected by it (only its dependencies would change).
• The most frequently used helper type Slice is not affected because it is in the System namespace (yes I know, but this makes life a lot easier!)
• Unfortunately, IVarTuple, STuple and TuPack are in Doxense.Collection.Tuples and will need to change namespace. Though with the introduction of ValueTuple and the (..., ..., ...) notation, and implicit conversions, I would guess most application use vanilla ValueTuples instead of STuples (which existed way before their introduction in .NET and C#).