The file-per-definition style should name files using similar conventions as IGP

[cmoesel]

From Saul Kravitz:

It would be very helpful if the names of the files in input/fsh/instances were similar to the JSON files output by the IGP, and included the FHIR resource type. For example: Observation-CauseOfDeathPart1-Example1.fsh instead of the current CauseOfDeathPart1-Example1.fsh. There is no easy way to map backwards to make that association from the generated FSH output.

I think we should consider doing this for all resource in the file-per-definition style (not just instances).