Add a new geocoder resource called adminAreas that is optimized for point in polygon queries

[mraross]

Looking up the admin area of a given address is becoming increasingly important to Location Services clients. Current WFS point in polygon queries against admin areas in BCGW are very slow. If we index admin area polygons using kernels (biggest contained bbox), we can dramatically improve performance of point in polygon queries.

Add a new adminAreas resource to the geocoder that uses kernels for fast response. Admin areas should be loaded from the authoritative source (e.g., BCGW).

Admin areas known to be of interest to location services clients include:

• Community Health Service Area
• Local Health Area
• Health Authority
• Health Service Delivery Area
• Electoral District
• Regional District
• Economic Development Zone