Change `printD` to print to a 'Debug' stream

STDERR is just a better place for this output.  Mind you, it doesn't
actually change anything about how it runs.  Still behaves the way
it has (in the terminal), just allows us to write scripts (hint hint)
and pipe the output.

scripts/ch_lib/util.py

@@ -1,5 +1,6 @@
 # -*- coding: UTF-8 -*-
 import os
+import sys
 import io
 import hashlib
 import requests
@@ -16,7 +17,7 @@ proxies = None
 
 # print for debugging
 def printD(msg):
-    print(f"Civitai Helper: {msg}")
+    print(f"Civitai Helper: {msg}", file=sys.stderr)
 
 
 def read_chunks(file, size=io.DEFAULT_BUFFER_SIZE):