Added basic concept of Mesh

Right now can create a quad or a cube.
Need a mesh renderer taht keep the buffer and all to optimally handle the mega buffer.

JulietApp/main.h

@@ -8,6 +8,7 @@
 
 namespace Juliet
 {
+    struct Mesh;
     struct GraphicsTransferBuffer;
     struct GraphicsBuffer;
     struct GraphicsDevice;
@@ -45,11 +46,14 @@ class JulietApplication : public Juliet::IApplication
     Juliet::GraphicsTransferBuffer* TransferBuffer   = {};
     Juliet::Texture*                DepthBuffer      = {};
 
+    Juliet::Mesh*  CubeMesh  = {};
+    Juliet::Arena* CubeArena = nullptr;
+
     Juliet::Arena* GameArena        = nullptr;
     Juliet::Arena* GameScratchArena = nullptr;
 
-    bool Running             = false;
     int  AutoCloseFrameCount = -1;
+    bool Running             = false;
 };
 
 JulietApplication& GetEditorApplication();