tor-bridge-relay Debian package

Inspired by https://trac.torproject.org/projects/tor/wiki/org/meetings/2014WinterDevMeeting/notes/BridgeBundles

tor-bridge-relay will be a small native package that recommends all bridge servers and contains a torrc that uses them.

We can also add bridge-specific documentation, e.g. advice like "if you are in country X then don't use transport Y because this opens your IP address up to a confirmation attack".

This should be fairly simple to implement, but I filed this bug to collect any comments that anyone might have.