This reverts commit 7827db36

Set default env[PATH] and env[HOSTNAME] since it is cleared by default setting clear_env = yes in php-fpm

- disabled database logging of sql reconnect errors, fixed #3974

- remove certificate renew config on domain deleting

- added 'certbot' to which command (if letsencrypt is not installed as system package, but certbot is)

add optional arrays for service-name to function system->getinitcommand and also a parameter to check if the current service exists (mandatory if you use an array)

Removed ubuntu1604.lib.php which is not required anymore.

- Introduced confid in $distver array to separate the config and class for a distribution in the installer.
- Cleaned up the dist detection.