[P/D][main]Offline the llmdatadist connector related parts of the code and files. (#4780)

### What this PR does / why we need it?
As support for the mooncake connector is now available, the llmdatadist
connector is no longer being maintained, so the llmdatadist-related
files need to be retired.

### Does this PR introduce _any_ user-facing change?
No

### How was this patch tested?
By ci

- vLLM version: v0.12.0
- vLLM main:
ad32e3e19c

---------

Signed-off-by: wangxiaoteng <wangxiaoteng@huawei.com>
Signed-off-by: liziyu <liziyu16@huawei.com>
Co-authored-by: liziyu <liziyu16@huawei.com>

tests/ut/kv_connector/utils.py

@@ -78,10 +78,9 @@ def create_vllm_config(
         enable_prefix_caching=True,
     )
     kv_transfer_config = KVTransferConfig(
-        kv_connector="LLMDataDistCMgrConnector",
+        kv_connector="MooncakeConnector",
         kv_role="kv_both",
-        kv_connector_module_path=
-        "vllm_ascend.distributed.llmdatadist_c_mgr_connector")
+        kv_connector_module_path="vllm_ascend.distributed.mooncake_connector")
     return VllmConfig(scheduler_config=scheduler_config,
                       model_config=model_config,
                       cache_config=cache_config,