raise upload size cap to ~1.86 GB and nginx timeouts to 1200s

Raise RequestSizeLimit/MultipartBodyLengthLimit on upload+replace-audio,
MaxUploadBytes in BatchUpload/BatchEdit, and DefaultResponseTimeoutSeconds to
1200s. Add client_max_body_size 2000m and proxy_read/send_timeout 1200s to the
nginx manager/public confs.

DeepDrftManager/appsettings.json

@@ -8,5 +8,9 @@
   "AllowedHosts": "*",
   "ForwardedHeaders": {
     "DisableHttpsRedirection": false
+  },
+  "Upload": {
+    "IdleTimeoutSeconds": 90,
+    "ResponseTimeoutSeconds": 1200
   }
 }