Refactor configs to have env in seperate yaml + Fix training

lerobot/common/policies/diffusion.py

@@ -0,0 +1,44 @@
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+from diffusion_policy.policy.diffusion_unet_image_policy import DiffusionUnetImagePolicy
+
+
+class DiffusionPolicy(nn.Module):
+
+    def __init__(
+        self,
+        shape_meta: dict,
+        noise_scheduler: DDPMScheduler,
+        obs_encoder: MultiImageObsEncoder,
+        horizon,
+        n_action_steps,
+        n_obs_steps,
+        num_inference_steps=None,
+        obs_as_global_cond=True,
+        diffusion_step_embed_dim=256,
+        down_dims=(256, 512, 1024),
+        kernel_size=5,
+        n_groups=8,
+        cond_predict_scale=True,
+        # parameters passed to step
+        **kwargs,
+    ):
+        super().__init__()
+        self.diffusion = DiffusionUnetImagePolicy(
+            shape_meta=shape_meta,
+            noise_scheduler=noise_scheduler,
+            obs_encoder=obs_encoder,
+            horizon=horizon,
+            n_action_steps=n_action_steps,
+            n_obs_steps=n_obs_steps,
+            num_inference_steps=num_inference_steps,
+            obs_as_global_cond=obs_as_global_cond,
+            diffusion_step_embed_dim=diffusion_step_embed_dim,
+            down_dims=down_dims,
+            kernel_size=kernel_size,
+            n_groups=n_groups,
+            cond_predict_scale=cond_predict_scale,
+            # parameters passed to step
+            **kwargs,
+        )