Organize functions with topical prefixes

[mpdougherty]

To help group the growing number of functions by type, functions could be organized using topical prefixes:

• map_ - Functions that produce maps.
• plot_ - Functions that produce plots (graph figures).
• metric_ - Functions that calculate metrics.
• check_ - Functions that check feature class schemas.
• report_ - Functions that produce reports.
• arc_ - Functions that import data from ESRI products using the arcgisbinding package.
• sf_ - Functions that convert to sf.
• util_ - Functions that don't warrant a unique group.