Map Endpoint

Create new /map endpoint to return the map.

changed milestone to %NSHM Model and Tool Improvements

added To Do label

assigned to @bclayton

mentioned in issue nshmp-apps#160 (closed)

mentioned in merge request !135 (merged)

added In Progress label and removed To Do label

mentioned in commit 691e8b50

closed with merge request !135 (merged)

removed In Progress label