Improve logging. Move print() statements to appropiate log().

Add COMFYUI and WEBHOOK logging and associated environment variable
control. Add WEBHOOK payload & request debug logs.

backend/config.py

@@ -119,6 +119,7 @@ log.info(f"GLOBAL_LOG_LEVEL: {GLOBAL_LOG_LEVEL}")
 
 log_sources = [
     "AUDIO",
+    "COMFYUI",
     "CONFIG",
     "DB",
     "IMAGES",
@@ -128,6 +129,7 @@ log_sources = [
     "OLLAMA",
     "OPENAI",
     "RAG",
+    "WEBHOOK",
 ]
 
 SRC_LOG_LEVELS = {}