add fhir-sandbox configs for lungair

[ebrahimebrahim]

Closes #9

• [x] add a fhir sandbox config that uses our EHR data from the LungAIR research collaboration
  • [x] heart rate
  • [x] fio2
  • [x] sao2
  • [x] pip
  • [x] peep
  • [x] respiratory rate
• [x] document in readme how to set up this sandbox fhir server if you have the EHR data table
• [x] add an alternative synthetic data mode for when a user doesn't have the EHR data table, since the data is not public but this open source project should be fully demonstratable
• [x] document in readme how to use the synthetic data mode

[ebrahimebrahim]

@jadh4v When reviewing this there is no need to look too carefully at the stuff in the fhir-sandbox-config directory as it's largely independent from the rest of the application. The main area where I could use your feedback is the README, which I reorganized quite a bit to accommodate the newly added things, i.e. check whether the organization makes sense, is the readme clear, do the instructions work, etc.