[pixels-cli, common] Implement Bucket-Based Data Classification for Distributed Loading

[AntiO2]

1. Refactor PixelsConsumer:

Introduce an abstract base class (AbstractPixelsConsumer) to handle common initialization and cleanup.

Create a concrete subclass (IndexedPixelsConsumer) dedicated to handling loads where a Primary Index exists.

Create a simple subclass (SimplePixelsConsumer) for loads without an Index (maintaining existing sequential logic).

2. Bucket-Based Routing Logic:

In IndexedPixelsConsumer, maintain a map to track active writers: Map<Integer, PerBucketWriter>.

For every incoming data row:

• Calculate the data's bucketId based on its Primary Key hash.

• Use the bucketId to look up the corresponding PerBucketWriter state object.

• If no writer exists for the bucketId, dynamically initialize a new PixelsWriter and temporary File.

3. Core Dependency: Node Mapping Cache:

Implement BucketToNodeCache (Small Component): Create a thread-safe, singleton, lazy-loaded cache component to quickly map a bucketId to its responsible RetinaNodeInfo. This cache reduces the necessity of repeatedly querying the NodeService for node assignment during the high-throughput loading process.

4. Distributed Indexing:

Ensure that index entries generated by IndexedPixelsConsumer are routed to the correct IndexService instance, potentially identified by the RetinaNodeInfo obtained from the cache.