There should be details relating to writing the 'fhir_hosts' file added to the README

[torstees]

For users that aren't already familiar with my ncpi_fhir_client fhir_hosts file, we need to explain what they need and how to set theirs up:

• Quick detail about who to contact (Natasha Singh) and what she'll need. That info should be in the slack thread from July
• Information about boiler plate settings that are common for everyone (and don't expose information that should be kept private, such as keys)
• Instructions on where the secret comes from (email) and where it goes in the fhir_hosts file.