twistd acme command for standalone issuing

[mithrandi]

There should be a twistd command that runs an issuing service standalone. This would be most useful with http-01 and dns-01 challenge types, putting certificates into a store (eg. a directory) for other software to use. (It would be possible to make it work for tls-sni-01 as well, for that matter, but that's probably a niche use case)

[twm]

https://github.com/glyph/lancer is basically this with some desktop integration features on top.

[adiroiban]

Is there any value in this, when you have certbot?

[mithrandi]

It's low priority, but txacme supports things that certbot doesn't, so I think there is still value. Maybe putting it in external projects like lancer is better though?