erp5_web_renderjs_ui: Fixup in obtaining the translation source file list

previous version would keep only one file ending in 'translation_data.js'
which was buggy. The scope here is to return all files,
but put those ending with 'translation_data.js' first,
so that it is more user friendly for user following the convention.

Again for user friendliness, we sort the lists alphabetically also

bt5/erp5_web_renderjs_ui/SkinTemplateItem/portal_skins/erp5_web_renderjs/Base_getTranslationSourceFileList.py

 filename_list = context.WebSection_getPrecacheManifest()
 
 file_list = []
-translation_data_file = []
+translation_data_file_list = []
 for filename in filename_list:
   if filename.endswith('.html'):
     file_list.append(filename)
@@ -9,7 +9,7 @@ for filename in filename_list:
 
   if filename.endswith('.js') and not only_html:
     if filename.endswith('translation_data.js'):
-      translation_data_file = [filename]
+      translation_data_file_list.append(filename)
       continue
     file_list.append(filename)
-return translation_data_file + file_list
+return sorted(translation_data_file_list) + sorted(file_list)