Remove complete time series aggregation example and add data collection service implementation

- Deleted `example_complete_series_aggregation.py` as it is no longer needed.
- Introduced `data_collection_service.py`, a production-ready service for cryptocurrency market data collection with clean logging and robust error handling.
- Added configuration management for multiple trading pairs and exchanges, supporting health monitoring and graceful shutdown.
- Created `data_collection.json` for service configuration, including exchange settings and logging preferences.
- Updated `CandleProcessingConfig` to reflect changes in timeframes for candle processing.
- Enhanced documentation to cover the new data collection service and its configuration, ensuring clarity for users.

config/data_collection.json

@@ -0,0 +1,69 @@
+{
+  "exchange": "okx",
+  "connection": {
+    "public_ws_url": "wss://ws.okx.com:8443/ws/v5/public",
+    "private_ws_url": "wss://ws.okx.com:8443/ws/v5/private",
+    "ping_interval": 25.0,
+    "pong_timeout": 10.0,
+    "max_reconnect_attempts": 5,
+    "reconnect_delay": 5.0
+  },
+  "data_collection": {
+    "store_raw_data": true,
+    "health_check_interval": 120.0,
+    "auto_restart": true,
+    "buffer_size": 1000
+  },
+  "trading_pairs": [
+    {
+      "symbol": "BTC-USDT",
+      "enabled": true,
+      "data_types": [
+        "trade",
+        "orderbook"
+      ],
+      "timeframes": [
+        "1m",
+        "5m",
+        "15m",
+        "1h"
+      ],
+      "channels": {
+        "trades": "trades",
+        "orderbook": "books5",
+        "ticker": "tickers"
+      }
+    },
+    {
+      "symbol": "ETH-USDT",
+      "enabled": true,
+      "data_types": [
+        "trade",
+        "orderbook"
+      ],
+      "timeframes": [
+        "1m",
+        "5m",
+        "15m",
+        "1h"
+      ],
+      "channels": {
+        "trades": "trades",
+        "orderbook": "books5",
+        "ticker": "tickers"
+      }
+    }
+  ],
+  "logging": {
+    "component_name_template": "okx_collector_{symbol}",
+    "log_level": "INFO",
+    "verbose": false
+  },
+  "database": {
+    "store_processed_data": true,
+    "store_raw_data": true,
+    "force_update_candles": false,
+    "batch_size": 100,
+    "flush_interval": 5.0
+  }
+}