Add Support for ACME EAB Credentials

[Forrest Fuqua]

In current scripts for managing ACME certs there is no support for EAB Credentials to be used. These are common for third party ACME servers to bind them to a account. for lego all you need is --eab --kid {EAB-KIB} --hmac {EAB-HMAC}

A free service that uses this is ZeroSSL's ACME but there are many more. I have hand edited /usr/bin/letsencrypt-certificates inside the letsencrypt-lego docker container to include these flags for lego hard coded and it does seem to be working normally.