Write a credit/edit FHIR server config function

[bamader]

Description:

Write a function to create/edit/upsert a FHIR server config in the database. This function should use a similar SQL pattern to what’s established in the valueset / query SQL statements, namely the `ON CONFLICT SET … EXCLUDED` block. This allows us to use one function for creating new FHIR servers as well as updating old servers by name.

Once this function is written, it should be wired up to the Create New Server button, as well as the Edit hover-over button in the table view This means we want to turn off the disabling for the field-changing boxes in the pop ups.

When a user clicks either Create Server or Save Changes, before persisting to the DB, we should call the same function we used in Test Connection in phase 1 to make sure the configuration is valid. We'll send a request to the /metadata page of the server, and if we get a 200 back, we'll persist to the DB. If not, we won't save the changes / new server and will instead alert the user.

Acceptance Criteria:

FHIR servers can now be created and updated from the front-end. Doing so should invoke test connection, which should allow valid configs to be persisted and not save invalid configs.

[linear]

QUE-102 Write a credit/edit FHIR server config function