Feature request: select server from add torrent dialog

[pataquets]

Thanks for writing and sharing this awesome software.
If you have multiple servers configured, it would be helpful to present a server selection drop-down in the add torrent dialog.
For instance, when you manage different servers for several users, or if you want to quickly add the same torrent to several of your servers.
Also, when sharing one torrent's magnet link from Tremotesf to Tremotesf itself to start downloading the same file from another server.