Implement kci email command with YAML configuration

[gctucker]

In the same way that we have other kci commands which rely on the YAML configuration, this is about adding a kci email sub-command with the configuration to determine which report to send to which recipients. Some users might adjust this via their own user accounts, but we also need some system-wide defaults e.g. to send all results about linux-next to the linux-next mailing list.

• YAML configuration added for email reports
• kci email CLI command implemented
• Tested locally