Update installer_base.lib.php to fix certbot webroot commands

Update installer_base.lib.php fixing certbot webroot command using --webroot-map as an alternative to version >=0.30.

I would also like to suggest @pixcept to add add support to acme.sh since he already did the acme.sh add up in https://git.ispconfig.org/ispconfig/ispconfig3/blob/master/server/lib/classes/letsencrypt.inc.php.