Isolated more web usages - Membership and Request stuff

- Moved a few more files

src/Umbraco.Core/Request/IRequestAccessor.cs

@@ -0,0 +1,8 @@
+namespace Umbraco.Core.Request
+{
+    public interface IRequestAccessor
+    {
+        string GetRequestValue(string name);
+        string GetQueryStringValue(string culture);
+    }
+}