Add a regenerate impostor button (#1057)

* Refresh the avatar dialog when impostor is deleted

* Adds a regenerate impostor button

This feature adds a button to regenerate an impostor, to save a few clicks

* Reload dialog after creating the impostor again to add a bit of delay for reloading

* Changed the icon to the refresh icon

html/src/localization/ja/en.json

@@ -817,6 +817,7 @@
                 "download_package": "Unity Packageをダウンロード",
                 "delete": "削除",
                 "delete_impostor": "インポスターを削除",
+                "regenerate_impostor": "Regenerate Impostor",
                 "create_impostor": "インポスターを作成"
             },
             "info": {