Tor.us Integration

[slavakurilyak]

Is your feature request related to a problem? Please describe.
Two issues: forcing Aragon users to sign up using MetaMask 👨‍🔧️and requiring technical knowledge of Ethereum to start using Aragon 🤓

Describe the solution you'd like
I want to provide mainstream users a gateway to Aragon using Google and other OAuth providers. This can be possible thanks to Tor.us integration. 🚀

Additional context
Tor.us supports several enabled OAuth logins to suit users signing in to their DApp, including:

1. Google
2. Facebook
3. Reddit
4. Twitch
5. Discord

Tor.us intends to add Github as an OAuth login in the future.

Github issue #900 is related.

[sohkai]

Thanks @slavakurilyak, we're looking into providers but won't be integrating Tor.us yet with #1277.