mod_unified_push: Add support for multiple token backends, including stoage Now that we have ACLs by default, it is no longer necessary to be completely stateless. On 0.12, using storage has benefits over JWT, because it does not expose client JIDs to the push apps/services. In trunk, PASETO is stateless and does not expose client JIDs.

This module writes out a traceback to `traceback.txt` in Prosodys data
directory (see `prosodyctl about`) when the signal `SIGUSR1` is
received. This is useful when debugging seemingly frozen instances in
case it is stuck in Lua code.