Add extra values to certificate model

Replaced system for extracting certificates

Allows for independent parsing of certificates for external tooling. Breaking change.

Make ProvisionedDevices Optional

Fixes #7

Many profiles do not have an associated list of devices such as app-store profiles as once signed it works on any. This commit has been tested through 70 profiles on my machine hopefully testing most iOS situations (macOS is still a question mark).

Update README