Make bounds on IML values available

nshmp-apps#93 (closed) adds the ability to enter an IML value into a form. It would be useful to dynamically query the bounds on the field.

That being said, the bounds on the return period field are hardcoded into the application (https://code.usgs.gov/ghsc/nshmp/nshmp-apps/-/blob/main/projects/nshmp-lib/src/lib/models/return-period.model.ts#L51), which may be appropriate in this case as well.

mentioned in issue nshmp-apps#93 (closed)

mentioned in merge request !642 (closed)

mentioned in merge request !643 (merged)

closed with merge request !643 (merged)

mentioned in commit e882b8e6