Backport ability for CSV loader to import the_geom / the_geom_webmercator in HEXEWKB

Conflicts:

	spec/lib/import_spec.rb
Allow to use CartoDB with any domain level

Conflicts:

	config/app_config.yml.sample
Use :DATABASE_USERNAME variable in private funcs
Separate load_functions from load_triggers tasks
Separate metadata functions in different files