caddy-frontend: Yet another TODO (trimming values)

software/caddy-frontend/TODO.rst

 Generally things to be done with ``caddy-frontend``:
 
  * tests: add assertion with results of promises in etc/promise for each partition
+ * generated files: ``| trim`` values (like ``slave_password[slave]`` in ``templates/template-log-access.conf.in``) in generated configuration files to have them renfered correctly
  * ``apache-ca-certificate`` shall be merged with ``apache-certificate``
 
    * ``apache-ca-certificate`` shall be appended to ``apache-certificate`` if not already there