update dependencies and add downloads page, various fixes

package.json

@@ -12,8 +12,12 @@
   "dependencies": {
     "@emotion/react": "^11.11.0",
     "@emotion/styled": "^11.11.0",
+    "@ffmpeg/core": "^0.12.10",
+    "@ffmpeg/ffmpeg": "^0.12.15",
+    "@ffmpeg/util": "^0.12.2",
     "@mui/icons-material": "^5.14.0",
     "@mui/material": "^5.14.0",
+    "browser-id3-writer": "^6.3.1",
     "react": "^18.2.0",
     "react-dom": "^18.2.0"
   },