Update INSTALL.rst and DEPLOY.rst based on Torflow's documentation

Are these things required for sbws:

  • 500Mbit-1Gbit of upstream documented in INSTALL.rst
  • a fixed IP address
  • SSL is needed to avoid HTTP content caches at the various exit nodes
  • Self-signed certs are OK
  • The server will consume around 12-15Gbytes/day
  • A script to create the file

See Torflow's docs at: https://gitweb.torproject.org/torflow.git/tree/NetworkScanners/BwAuthority/README.BwAuthorities#n157

This documentation needs to be updated in 1.0, before we give the instructions to more authority operators.