Allow multiple files to be uploaded at once

Modules/Media/Assets/js/components/UploadButton.vue

@@ -21,6 +21,7 @@
             :on-success="handleSuccess"
             :show-file-list="false"
             :http-request="uploadFile"
+            multiple="true"
             style="display: inline-block; margin-right: 10px;">
         <el-button size="small" type="primary" style="padding: 11px 9px;" :loading="fileIsUploading">Upload File</el-button>
     </el-upload>

public/js/app.js

@@ -94705,6 +94705,7 @@ exports.default = {
 //
 //
 //
+//
 
 /***/ }),
 /* 159 */
@@ -94724,7 +94725,8 @@ var render = function() {
         "on-remove": _vm.handleRemove,
         "on-success": _vm.handleSuccess,
         "show-file-list": false,
-        "http-request": _vm.uploadFile
+        "http-request": _vm.uploadFile,
+        multiple: "true"
       }
     },
     [