Change:
- Initial set of changes for renaming to ansible-core
- Includes changelog fragment changes from base -> core
- Does NOT include docs changes
- Modifies detection stuff in setup.py to support ansible<2.9 and ansible-base
Test Plan:
- ci_complete
* Rename `tests` test to match plugin type.
* Rename `test_infra` test to avoid confusion.
This test target is not a test for test plugins.
* Rename `vars_prompt` test to avoid confusion.
* Update sanity ignores.
