Adds Postgis support to database

Using active record postgis adapter, as this seems to be the most used
gem.
Adds geometry parsing to the data standard

Since we're using activerecord-postgis-adapter, we can create geometries
from WKT. You can also use RGeo objects, but WKT is much more
portable/future-proof.
Adds DB schema entry for postgis adapter
Adds geometry attribute to ProtectedArea model
Adds db schema entry for the Designation-Jurisdiction relation
Adds a WDPA ID attribute to ProtectedArea
Adds WDPA Parent ID to Protected Area
Documentation for CartoDB importer
Adds Name to Protected Area
Adds original name to Protected Area
Adds marine status to ProtectedArea
Adds reported marine area to ProtectedArea
Adds reported area to Protected Area
Adds GIS area to Protected Area
Adds GIS marine area to Protected Area
Fixes a typo in the PA reported marine area attribute
Creates a many-to-many relationship between Countries and PAs
Creates a many-to-many relationship between sub locs and PAs
Adds Legal Status relationship to Protected Area
Creates IUCN Category relation on Protected Area