Be your own SSL certificate authority

Changes for 0.19 - 2023-10-05T15:21:23Z

• Add support for --ext for ex "subjectAltName=DNS:example.com"
• Add "subjectAltName=DNS:$domainname" as default for "generate" sub command
• Add copy_extensions=copy to copy subjectAltName from csr to crt
• Add --help and -h