Rewrite SMTP Notifier to use MIME::Tools (instead MIME::Lite)
Add API call for sending notification, add testmail for smtp

The api method send_notifcation allows for triggering the notification
backend to send a preconfigured notification. A testmail is included in
the config set to allow easy testing of the smtp setup.
Add a first draft oft openxpkicli binary as simple command interface

The openxpkicli offers a simple interface to the openxpki api to execute
arbitrary commands. Needs further testing and improvement.
See perldoc for usage details.
Refactoring of Workflow Factory to match the patched upstream version

Replace the workaround of the wrapped workflow class by the features
invented by our upstream patch on Workflow.pm.
There is still a bug in 1.35_1 upstream so we depend on the 1.36 which
will hopefully include the necessary fix.