Move latent scale factor from VAE to model.

comfy/latent_formats.py

@@ -0,0 +1,16 @@
+
+class LatentFormat:
+    def process_in(self, latent):
+        return latent * self.scale_factor
+
+    def process_out(self, latent):
+        return latent / self.scale_factor
+
+class SD15(LatentFormat):
+    def __init__(self, scale_factor=0.18215):
+        self.scale_factor = scale_factor
+
+class SDXL(LatentFormat):
+    def __init__(self):
+        self.scale_factor = 0.13025
+