util.sasl.external: never returning a failure if no valid address is found?!
util.sasl.external: code refactor,
- Consistently have the backend perform all sanity check (including checking for user existence).
- The processing handler shall handle only the eventual username / boolean and error.
util.sasl.external: fix log handler.
pubsub_aux.lib: add missing semicolon.
sasl_aux.lib: first commit, move shared backends to a module library to prevent code loops.
util.sasl.external: remove the shared backend from the util.
mod_auth_internal_{hashed/plain}: reflect changes in previous commits.