Telepathy Phoenix echo bot & tester

Phoenix is a echo bot for the telepathy framework re-using the standard
Telepathy infrastructure. Mission control is used for the account management,
standard Telepathy clients are used for the echo implementation.

To setup the echo bot, configure and enable the echo bot account in
mission-control (using mc-tool for example). If passwords are requried, the
authentication handler for Phoenix can only handle the X-TELEPATHY-PASSWORD
mechanism and expects to find the password in a file called phoenix/auth under
XDG_CONFIG_HOME (normally ~/.config). The format of this file is simply, one
line for each account containing:
  <account path suffix> <password>