ckanext-spatial Py3 + CKAN 2.9 support

[thejuliekramer]

User Story

As a data.gov developer, I want ckanext-spatial running with CKAN 2.9 and Python 3 so that we can move out of CKAN 2.8 and reduce our technical debt and meet compliance standards.

Acceptance Criteria

• WHEN I view CI
  THEN I see a successful job testing the extension under CKAN 2.9
  AND I see a successful job testing the extension under CKAN 2.8
  AND I see a successful job testing the extension under the legacy test environment
• WHEN I remove the tests
  THEN I see CI fail due to test coverage being below a threshold

Background

CKAN 2.9 extension tracker.

Details / tasks

ckanext-spatial has an existing branch to support Python 3 ckan/ckanext-spatial#249

Use the fork of ckanext-spatial for now and see how we can support merging of this PR.

[jbrown-xentity]

This is an upstream repo that now supports Py3, nothing to do.