Ability to overwrite image extensions

[Joost Koopmans]

I want to be able to overwrite the imageExtensions array in the settings/store.js. Now only some settings are manually overwritable:

// overwrite headers - Axios
    if (Object.prototype.hasOwnProperty.call(data, 'headers')) {
      state.headers = data.headers;
    }
    // base url - axios
    if (Object.prototype.hasOwnProperty.call(data, 'baseUrl')) {
      state.baseUrl = data.baseUrl;
    }
    // windows config
    if (Object.prototype.hasOwnProperty.call(data, 'windowsConfig')) {
      state.windowsConfig = data.windowsConfig;
    }
    // language
    if (Object.prototype.hasOwnProperty.call(data, 'lang')) {
      state.lang = data.lang;
    }
    // add new translation
    if (Object.prototype.hasOwnProperty.call(data, 'translation')) {
      Vue.set(state.translations, data.translation.name, Object.freeze(data.translation.content));
    }