Add i18n releted changes

I created some main optional parameters for change main texts on this editor. These are can be null. I hope this pr please you. This parameters helps people can change easily main texts, I'll use these parameters for multi language support. I had to fix saving issue on iOS so this pr included that fix.

StoriesEditor(
  giphyKey: '[YOUR GIPHY API KEY]', /// (String) required param
  onDone: (String uri){
    /// uri is the local path of final render Uint8List
    /// here your code
  },
  colorList: [], /// (List<Color>[]) optional param 
  gradientColors: [], /// (List<List<Color>>[]) optional param 
  middleBottomWidget: Container(), /// (Widget) optional param, you can add your own logo or text in the bottom tool
  fontFamilyList: [], /// (List<String>) optional param
  isCustomFontList: '', /// (bool) if you use a own font list set value to "true"
  onDoneButtonStyle: Container(), /// (Widget) optional param, you can create your own button style
  onBackPress: /// (Future<bool>), optional param, here you can add yor own style dialog
  editorBackgroundColor: /// (Color) optional param, you can define your own background editor color
  galleryThumbnailQuality: /// (int = 200) optional param, you can set the gallery thumbnail quality (higher is better but reduce the performance)
  tapToTypeText: '', // optional param, default:  "Tap to type",
  doneButtonText: '', // optional param, default:  "Done",
  discardDialogTitleText: '', // optional param, default:  "Discard Edits?",
  discardDialogDetailText: '', // optional param, default: "If you go back now, you'll lose all the edits you've made.",
  discardDialogDiscardButtonText: '', // optional param, default:  "Discard",
  discardDialogCancelButtonText: '', // optional param, default:  "Cancel",
  discardDialogSaveDraftButtonText: '', // optional param, default:  "Save Draft",
  saveDraftAlertEmptyText: '', // optional param, default:  'Draft Empty',
  saveDraftAlertErrorText: '', // optional param, default:  'Error',
  saveDraftAlertSavedText: '', // optional param, default: 'Successfully saved',
  framesText: '', // default: frames, you can add \n to it for next line
  prepairingText: '', // default: preparing, you can add \n to it for next line
  renderingText: '', // default: rendering, you can add \n to it for next line
  recordingSuccessText: '', // default: 'Recording successfully saved',
  recordingErrorText: '', // default: Gallery saver error,
 )

camilo1498 / stories_editor

Add i18n releted changes #16