Improve docs for tor setup

[placer14]

Several tickets have been raised indicating that setting up tor is non-trivial and error-prone. Would be good to take a holisitic look at our documentation to see if the information for tor setup is sufficient or needs improvement. Looking for assistance with testing our current tor setup instructions on Windows, Ubuntu and Mac and providing feedback and/or doc updates to ensure others have a better experience walking through these steps in the future.

Validate on:

• Windows
• Ubuntu
• Mac

Here are a few related issues where others have found problems with the setup which might also indicate areas of documentation which are lacking:

• starting OB2 with --tor, get errors: transport conductor failed, connect: connection refused #1605
• Dual-stack Tor: unable to query any ticker API #1558
• Gateway (JSON-API) connections via Tor #794