Clean code, avoid indirect variables and single quotes for delayed expansion.

While testing or setting up getssl the installation of certificates
could fail. Option -i allows to copy and reload service quicker.

Despite changing working dir from command line covers most usage cases,
others defaults are also usefull like /etc/getssl, SCRIPTDIR/conf or
SCRIPTDIR/.getssl. Last candidate (~/.getssl) is used if no config file
was found in previous paths.

The trailing slash of the Let's Encrypt staging server URL broke API discovery

Recent versions of gawk have upgraded the regex processing with l10n
based character classes. Replace use of these so other versions of awk
can be used.

Debian dnsutils 1:9.11.5.P4+dfsg-5.1 errors on -debug=1

Dnsutils version 1:9.10.3.dfsg.P4-12.3+deb9u4 and version 1:9.2.1-2.woody.2
(from 2003) accept both -debug=1 and -debug so I've changed this globally.

ACMEv2 during testing