Naming pattern for IAM functions

**Is your feature request related to a problem? Please describe.**
It may be easier for users to find and select IAM functions if the function names start with the prefix `iam`, e.g., `iam_ashrae` rather than the current pattern placing `iam` as a suffix `ashraeiam`

**Describe the solution you'd like**
Rename `physicaliam`, `ashraeiam`, etc. and deprecate old names.


