Add torrc option for non-anonymous SocksPort

Some single onion service users want to use the running tor instance for a single onion service, and fetching files over tor. They don't care about their anonymity.

One workaround for this issue is to compile tor with --enable-tor2web-mode. Another is to run a separate tor instance for file transfers.

We could add a SocksPortNonAnonymousMode to make this easier, but that could also make it easier for users to lose their anonymity.