Explicitly import URL

With Yarn PnP, URL is seems to not automatically be
part of the global scope.

Signed-off-by: David Mehren <git@herrmehren.de>

src/media/backends/webdav-backend.ts

@@ -5,6 +5,7 @@
  */
 import { Inject, Injectable } from '@nestjs/common';
 import fetch, { Response } from 'node-fetch';
+import { URL } from 'url';
 
 import mediaConfiguration, { MediaConfig } from '../../config/media.config';
 import { MediaBackendError } from '../../errors/errors';