Add profiles for MedicationTreatmentLine, MedicationTreatment, MedicationOverview, Medication

[costateixeira]

MedicationTreatmentLine (we use MedicationStatement, see #5)

• Align with Medications section of IPS (shall not conflict)
• Add intro to MedicationStatement profile to show the rationale - compatibility with IPS; keeping broad semantics of "list" (not only prescribed or dispensed or patient-stated...)

MedicationOverview (Documents? List? )

• Clarify the intent based on the use cases: Do we have authored, signed documents? Do we have on-demand creation of documents?
• add intro page to share why we choose each option
  Even wih List, we need at least Provenance.
• Add link to HL7 core operation: https://build.fhir.org/lifecycle.html#current

MedicationTreatment (CarePlan?)
(leave out of scope for now? - leave a reference in the logical model overview)

Medication:

• use the LM
• see if it can be further simplified
• Do we need a common medication model across profiles, avoiding repeating extensions? If so, where would that live?