mod_prometheus: Ensure mod_http is loaded where the http interface is exposed (thanks Martin) Loading mod_http globally does not have the desired effect, it needs to be loaded in the host context where module:provides is called.

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summary: Log a message once per minute
...

This module sends `-- MARK --` to the log once per minute. This may be
useful to give a sense of how busy the server is or see that logging and
timers are still working.