rework sd1.5 and sdxl from scratch

backend/args.py

@@ -57,3 +57,9 @@ parser.add_argument("--cuda-stream", action="store_true")
 parser.add_argument("--pin-shared-memory", action="store_true")
 
 args = parser.parse_known_args()[0]
+
+# Some dynamic args that may be changed by webui rather than cmd flags.
+dynamic_args = dict(
+    embedding_dir='./embeddings',
+    emphasis_name='original'
+)