Toddbell/asmdef editor (#115)

* Update PlayFabEditorExtensions.asmdef

At this moment, the .asmdef will force the EditorExtensions into their own dll (not wrapped into Unity's Editor dll) Which has the consequence that a CompilationPipeline will return the editor extensions when Play is passed in (rather than Editor which it should show up in).

* Need to move the asmdef file under an Editor folder

Since we only target the Editor, this asmdef file has to be in the Editor foler, not the parent folder that contained it.

Author: toddbellMSFT