Let's Encrypt provide API to fully automate (gain/renew) certificate retrieval using ACME protocol. Integrate this capability into wildfly.

This can simplify administrator work. No need to perform certification renewal routine tasks.

This is follow up on WFCORE-3305 and piece of bigger task "Simplify SSL configuration in wildfly". That said it is just "User experience" issue. Administrator still can work with Let's Encrypt by third party client and just reference wildfly to this certificate.

[1] Latest draft: https://tools.ietf.org/html/draft-ietf-acme-acme-10