closes #6414

Can set zero lenght password on constructor 

Patch taken from https://forum.howtoforge.com/threads/monitoring-mysql-mariadb-annoying-aborted-connection-on-var-log-mysql-error-log-hack.89045/

- Updated edit links in html template

This allows sites using redirect=proxy to still generate ACME
certificates by not passing the acme requests through to the proxy.

We should also consider using this for other features available such as
own error documents, SSI and custom directives.