re-work multi --styles-file

--styles-file change to append str
--styles-file is [] then defaults to [styles.csv]

--styles-file accepts paths or paths with wildcard "*"

the first `--styles-file` entry is use as the default styles file path
if filename a wildcard then the first matching file is used
if no match is found, create a new "styles.csv" in the same dir as the first path

when saving a new style it will be save in the default styles file
when saving a existing style, it will be saved to file it belongs to

order of the styles files in the styles dropdown can be controlled to a certain degree by the order of --styles-file

modules/shared.py

@@ -1,3 +1,4 @@
+import os
 import sys
 
 import gradio as gr
@@ -11,7 +12,7 @@ parser = shared_cmd_options.parser
 
 batch_cond_uncond = True  # old field, unused now in favor of shared.opts.batch_cond_uncond
 parallel_processing_allowed = True
-styles_filename = cmd_opts.styles_file
+styles_filename = cmd_opts.styles_file = cmd_opts.styles_file if len(cmd_opts.styles_file) > 0 else [os.path.join(data_path, 'styles.csv')]
 config_filename = cmd_opts.ui_settings_file
 hide_dirs = {"visible": not cmd_opts.hide_ui_dir_config}