Announce onion address in HTTP header

[jzbz]

Enabling Onion-Location will inform Tor Browser users who hit the plain dcrdata URL that a Tor hidden service is available and provide them the onion address.

https://community.torproject.org/onion-services/advanced/onion-location/

[chappjc]

Pretty cool. We can even build off of commit 516d701 to add a <meta http-equiv="onion-location" content="http://<your-onion-service-address>.onion" /> attribute to the html head element to achieve the same effect without tweaking the reverse proxy.

[chappjc]

I hacked it into the header via nginx for now.

BTW, I really should move the hidden service host to europe since most of the relays, guards, and exits are there.

[ukane-philemon]

@chappjc, is this still relevant? I can add that info in the HTML head.