Add "Request Attachments" content as Draft

see notes from  2022-05-25 CDex/HRex Meeting

Includes:

1. Updating documentation in introduction to guide
2. Updating documentation in background page:
   1.  New Section and Diagram under Attachments
3. Updating documentation task-based page:
   1. add new input parameters or create new Task Profile
      1. output as operation boolean
      2. Payer ID
      3. Tracking ID
      4. lines nos
      5. LOINCs
      6. Due Date
      7. Date of Service
      8. Member ID
      9. Payer URL
      10. Patient Name
      11. Patient Account No.
      12. DOB (optional)
   2. example
   3. map data element to Task elements
4. Updating documentation attachments page:
   1. document fhir-based vs non-fhir based reuqests
   2. add sequence diagrams for:
      1. unsolicited
      2. non-fhir solicited request
      3. fhir solicited request
   3. add example scenarios for each.
5.  Update Operation Definition
   1. Payer ID
   2. Payer URL
   3. Tracking ID
   4. line nos
   5. LOINCs
   6. member ID
   7. Date of Service