refactor: consolidate error handling and retry configuration

Centralize the error channel size, retry policy and max-failed batches/partition limits in the job config.

config.yaml

@@ -3,15 +3,19 @@ source_db_type: sqlserver
 target_db_type: postgres
 
 defaults:
-  max_extractors: 2
-  max_loaders: 4
-  queue_size: 8
-  batch_size: 25000
   batches_per_partition: 8
+  max_extractors: 2
+  extractor_batch_size: 25000
+  extractor_queue_size: 8
+  max_transformers: 2
+  transformer_batch_size: 25000
+  transformer_queue_size: 8
+  max_loaders: 4
+  loader_batch_size: 25000
   truncate_target: true
   truncate_method: TRUNCATE # TRUNCATE | DELETE
   max_partition_errrors: 5
-  max_chunk_errors: 5
+  max_extractor_batch_errors: 5
   retry:
     attempts: 3
     base_delay_ms: 500