Publication cleanup

[jddamore]

This is a mash-up of many adjustments and fixes to the IPS build before publication. This addresses a set of specific JIRA issues including:

Specific JIRA issues

• Broken links
  -- https://jira.hl7.org/browse/FHIR-35112?filter=15803
  -- https://jira.hl7.org/browse/FHIR-31396?filter=15803
• Should mention joint work with IHE on transport (https://jira.hl7.org/browse/FHIR-30076?filter=15803)
• Allow 0..* for Immunization Performer (https://jira.hl7.org/browse/FHIR-31049?filter=15803)
• Remove confusing comment in multiple codes (CodeableConcept) (https://jira.hl7.org/browse/FHIR-34824?filter=15803)
• Allow different types of Performers in Observation (lab, rad + path) (https://jira.hl7.org/browse/FHIR-26668?filter=15803)
• Wrong text in medication example https://jira.hl7.org/browse/FHIR-32902?filter=15803

In addition to these specific JIRA tickets, these edits were also reviewed at the IPS weekly meeting (4/28/2022):

• Change "ISO/DIS 27269" to "ISO 27269"
• Make sure all links are working (in addition to broken links)
• Provide descriptions on $summary operation
• Modify text on open-slicing since plan is to no longer use via vocab
• Condition.onset / Condition.abatement / AllergyIntolerance.onset relaxing types
• Modify text on medication lists since MedicationRequest is now permitted
• Add text relating to language translation expectations
• Revise text/link in Design to SNOMED IPS Terminology
• Resolve issues in example that were causing "broken link" error in QA

[jddamore]

@rhausam I suggest that you merge this one first and then rebase others. Let me know if any questions on review.

[rhausam]

Ready to merge.