feat: download shared subdirectory (#1184)

Co-authored-by: Oleg Lobanov <oleg@lobanov.me>

frontend/src/api/utils.js

@@ -36,6 +36,8 @@ export async function fetchJSON (url, opts) {
 export function removePrefix (url) {
   if (url.startsWith('/files')) {
     url = url.slice(6)
+  } else if (store.getters['isSharing']) {
+    url = url.slice(7 + store.state.hash.length)
   }
 
   if (url === '') url = '/'