Move ILinksExtensions to Platform::Data namespace and move extensions from ILinks

[FreePhoenix888]

#85 should be complete before the start of this task.

• Change namespace
• Move these extensions to ILinksExtensions
• Make functions to accept first argument that matches CLinks concept

[Konard]

We can make it Links namespace as in the Collections repository:
https://github.com/linksplatform/Collections/blob/40c2da07dc2e49b7964ec151ec0ae743523b1782/cpp/Platform.Collections/Sets/ISetExtensions.h#L1

Platform::Data

But this still be the ILinksExtensions.h file.