refactor Let's encrypt issuing and introduce ECC cert handling #5226 #6563

install/tpl/server.ini.master

interface/lib/classes/validate_domain.inc.php

interface/web/admin/form/server_config.tform.php

interface/web/admin/lib/lang/en_server_config.lng

interface/web/admin/templates/server_config_web_edit.htm

server/cli/modules/letsencrypt.inc.php

server/lib/classes/cron.d/800-letsencrypt_cleanup.inc.php

server/lib/classes/letsencrypt.inc.php