NuCivic/nucivic-internal#43
    + Adding site_read endpoint
    + Adding revision_list method.
    + Adding revision_list method and package_revision_list from code.
    + Adding help to ckan_current_package_list_with_resources method. Fixing offset and limit argument in open_data_schema_map_endpoint_special_arg
    + Adding multiple schema support by module
    + Adding CKAN schemas by entity
    + Fixing open_data_schema_apis_features_export to support multiple schemas
    + Fix open_data_schema_map_endpoint_process_map to load a single entity
    + Adding group package show endpoint and alter query hook