Release control for JSS scripts
This is a major refactoring and re-write.
And, I've refactored the core of the tool in such a way that it is now hopefully simple to add support for other Version Control systems, or potentially support other types of JSS object.
I've also added lots of pytest tests, again with the hope of making it easy to extend the tool in future.
Add support for storing passwords in keychain by default
keyring
module by default to safely store passwords (Issue #1)