Use stagging letsencrypt endpoint

[doanguyen]

Instead of production endpoint, which will be throttled

[nguyenkims]

@doanguyen yeah using the staging endpoint during the development is a good idea 👌! Maybe this can be set via a environment variable like TESTING?

[doanguyen]

sure, at the moment, the acme-challenge is done during the build phase in the Dockerfile, we will need to move it to the entrypoint instead.

Ref: 0. acme stagging server: https://certbot.eff.org/docs/using.html#changing-the-acme-server

[smargold476]

Hi @doanguyen @nguyenkims are you still using the simplelogin-postfix-docker project? Looks like nobody is maintaining that project? Do you have any Information? Regards

[rehanone]

Closing this issue as per the discussion on #4, it is not required/planned.