message: Add file decorator in file question for vue
diff: <template>
  <div :class="question.cssClasses.root">
  <input :class="question.cssClasses.fileInput" v-if="!question.isReadOnly" type="file" :id="question.inputId" @change="doChange" v-bind:aria-required="question.isRequired" :aria-label="question.locTitle.renderedHtml" :multiple="question.allowMultiple ? 'multiple' : undefined" v-bind:title="question.inputTitle" v-bind:accept="question.acceptedTypes" />
  - <button type="button" v-if="!question.isReadOnly && !question.isEmpty()" :class="question.cssClasses.removeButton" @click="doClean">{{question.cleanButtonCaption}}</button>
  <input v-if="question.isReadOnly" type="file" disabled :class="getPlaceholderClass()" :placeholder="question.title" style="color: transparent;"/>
  + <div :class="question.cssClasses.fileDecorator">
  + <label :class="question.cssClasses.chooseFile + (question.isReadOnly ? ' ' + question.cssClasses.disabled : '')" :for="question.inputId">{{question.chooseButtonCaption}}</label>
  + <span :class="question.cssClasses.noFileChosen" v-if="question.isEmpty() && !question.isReadOnly">{{question.noFileChosenCaption}}</span>
  + </div>
  + <button type="button" v-if="!question.isReadOnly && !question.isEmpty()" :class="question.cssClasses.removeButton" @click="doClean">{{question.cleanButtonCaption}}</button>
  <div v-if="!question.isEmpty()">
  <span v-for="(val, index) in question.previewValue" :key="question.inputId + '_' + index" v-show="val" :class="question.cssClasses.preview">
  <div v-if="val.name">
  