Unify the C direct client and cluster client

### 🚀 Feature Description and Motivation

Currently, there're two C clients.
- The direct C client already exists (client/priskv.h) that connects directly to the server without Redis.
- The cluster C client (cluster/client/client.h) supports redis based solution

Python binding only supports cluster.


### Use Case

unify the client

### Proposed Solution

_No response_