[Refactor]Refactor of vllm_ascend/distributed module (#5719)

### What this PR does / why we need it?
Based on the RFC:https://github.com/vllm-project/vllm-ascend/issues/5604

This PR is a refactoring of vllm_ascend/distributed, moving all
kv_transfer realtaed codes into a dedicated folder, which has already
been done in vLLM

### Does this PR introduce _any_ user-facing change?
NA

### How was this patch tested?


- vLLM version: v0.13.0
- vLLM main:
2f4e6548ef

---------

Signed-off-by: lty <linhebiwen@gmail.com>

vllm_ascend/distributed/kv_transfer/__init__.py

@@ -0,0 +1,45 @@
+#
+# Copyright (c) 2025 Huawei Technologies Co., Ltd. All Rights Reserved.
+# This file is a part of the vllm-ascend project.
+#
+# 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.
+#
+
+from vllm.distributed.kv_transfer.kv_connector.factory import \
+    KVConnectorFactory
+
+
+def register_connector():
+    KVConnectorFactory.register_connector(
+        "MooncakeConnectorV1",
+        "vllm_ascend.distributed.kv_transfer.kv_p2p.mooncake_connector",
+        "MooncakeConnector")
+
+    KVConnectorFactory.register_connector(
+        "MooncakeConnectorStoreV1",
+        "vllm_ascend.distributed.kv_transfer.kv_pool.ascend_store.ascend_store_connector",
+        "AscendStoreConnector")
+
+    KVConnectorFactory.register_connector(
+        "AscendStoreConnector",
+        "vllm_ascend.distributed.kv_transfer.kv_pool.ascend_store.ascend_store_connector",
+        "AscendStoreConnector")
+
+    KVConnectorFactory.register_connector(
+        "MooncakeLayerwiseConnector",
+        "vllm_ascend.distributed.kv_transfer.kv_p2p.mooncake_layerwise_connector",
+        "MooncakeLayerwiseConnector")
+
+    KVConnectorFactory.register_connector(
+        "UCMConnector", "vllm_ascend.distributed.kv_transfer.ucm_connector",
+        "UCMConnectorV1")