Apache mod_md support
I know that ISPConfig have letsencrypt support thru external scripts, but can you please add support for enabling letsencrypt using mod_md directly in apache?
I think, you can by default include following in all generated virtualhosts (obviously with modified MDomain list):
<IfModule md_module>
MDomain domain.cz www.domain.cz
MDCertificateAgreement https://letsencrypt.org/documents/LE-SA-v1.2-November-15-2017.pdf
</IfModule>
That way it will automaticaly manage HTTPS certificates for domains on servers which have mod_md installed and will not affect others. It might not make sense in all cases (eg. if you need to use certs outside of apache, eg. for mailserver. in that case you can load certs from /etc/apache2/md, but i am not sure that makes much sense). But mod_md is on it's way to all major distros. And it might be desirable in pure webhosting setups, where you want to enable HTTPS globally. Also it seems to be quite easy to implement.