Add Automated Tests

[Sherlouk]

We should add test coverage to both the command line tool and the iOS framework exploring all code routes.

We should add coverage for negative scenarios, such as using a PEM certificate and the invalidCertificate error.

We should set this up to run on GitHub Actions automatically for each commit.

If possible, we should explore writing a UI test which lets us install the mobileconfig and see the 'Locked'/'Unlocked' status change at the correct times.