Feature/prism fhirpath formatting

[brianpos]

New script and css to be available for any implementation guide to support syntax highlighting for fhirpath markdown blocks (since the scripts need to be in an approved template)

eg.

Patient.name.exists()
Patient.identifier.exists(use = 'official')
Patient.telecom.exists(system = 'phone' and use = 'mobile')
Patient.generalPractitioner.exists(resolve() is Practitioner) // this example is wrong