Upload Directories via Web

This implements the option to choose directories when uploading files via the Web UI (The most important part of #52).

When you choose a directory, its file and sub-directory structure will be maintained.

Tested with the latest Safari, Firefox, and Chrome.

Additionally, the Deno version was updated, which required some accessibility improvements as well.

islands/news/Feeds.tsx

@@ -252,12 +252,14 @@ export default function Feeds({ initialFeeds }: FeedsProps) {
                 <button
                   class={`text-white block px-4 py-2 text-sm w-full text-left hover:bg-slate-600`}
                   onClick={() => onClickImportOpml()}
+                  type='button'
                 >
                   Import OPML
                 </button>
                 <button
                   class={`text-white block px-4 py-2 text-sm w-full text-left hover:bg-slate-600`}
                   onClick={() => onClickExportOpml()}
+                  type='button'
                 >
                   Export OPML
                 </button>