Compacts migrations to reduce number required to db setup

Move indexes for country geometries in to migrations
Refactors Countries Geometries Importer

Shifts all responsibility from the rake task so that the class can
handle the complexities.
Merge branch 'viz-stats' of github.com:unepwcmc/ProtectedPlanet into viz-stats

* 'viz-stats' of github.com:unepwcmc/ProtectedPlanet:
  fixes rake task typo
  split_country_marine query - fix geoms before intersection
  removed a todo comment
  added condition to dissolve_country query and fixed tests
  Added marine_eez_pas_geom and marine_ts_pas_geom to countries table and added queries to geometry module