Provide instructions how to setup letsencrypt

[mpurzynski]

It would be nice to have instructions how to deploy the letsencrypt certificate for the webserver that hosts the update files and the resulting mix.

[ahkok]

Agreed, and we have certbot to make it really easy, too.

[chuckn408]

--Running "man certbot" will give very detailed instructions on how to set up a "letsencrypt" certificate.
--More unique details/instructions are provided at https://letsencrypt.org/getting-started/