Log Message:
Update ejabberd to 15.03. Take on maintainership.

- Add support for WebSocket
- Flexible session management with multiple backends: Mnesia/SQL/Redis or
  custom backend for session manager
- Security improvement with SCRAM based password encryption in SQL
  authentication backends.
- Package management for ejabberd contributed modules
- Improved Elixir experience
- Automatic clustering scripts
- Added missing index on database
- Important updates on the documentation, with the launch of a new
  documentation site: docs.ejabberd.im
- Several other bugfixes

More information on release at

  https://www.ejabberd.im/node/24818