v0.2.0 - Voice support

• Added initial voice transmission support, including queuing and ffmpeg support.
• Changed from println! to using the log crate for logging.
• Added UserSettings to the model, events, and state tracking.
• Added support for gateway migration.
• Added REST endpoints:
  • get message log
  • edit/delete/acknowledge message
  • create/get private channel
  • get user avatar