Commit Briefs
rework gencert(); make gemexp generate EC certs
Taking inspiration from acme-client.
gg: exit with the gemini response code
0 is still used for 2X replies, and "external" failures (e.g. network, tls, ...) are still using exit code 1. Gemini non-2x replies now get their response code reported as-is as status code.
tweak gemexp logs
gemexp is meant for local testing so I'm not too worried about changing its log format if it makes sense to do so.