[LLM] First commit the llm deployment code

fastdeploy/model_executor/layers/backends/__init__.py

@@ -0,0 +1,29 @@
+# Copyright (c) 2025 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""
+all backends methods
+"""
+
+from .xpu import *
+from .npu import *
+
+__all__ = []
+from . import npu
+if hasattr(npu, '__all__'):
+    __all__.extend(npu.__all__)
+    
+from . import xpu
+if hasattr(xpu, '__all__'):
+    __all__.extend(xpu.__all__)