feat: make hash generation multi-threaded, change --rebuild-hash-cache from bool to int

keep in mind that most likely the drive is going to be the bottleneck now

modules/util.py

@@ -176,13 +176,11 @@ def generate_temp_filename(folder='./outputs/', extension='png'):
 
 
 def sha256(filename, use_addnet_hash=False, length=HASH_SHA256_LENGTH):
-    print(f"Calculating sha256 for {filename}: ", end='')
     if use_addnet_hash:
         with open(filename, "rb") as file:
             sha256_value = addnet_hash_safetensors(file)
     else:
         sha256_value = calculate_sha256(filename)
-    print(f"{sha256_value}")
 
     return sha256_value[:length] if length is not None else sha256_value