* Move ansible.compat.tests to test/units/compat/.
* Fix unit test references to ansible.compat.tests.
* Move builtins compat to separate file.
* Fix classification of test/units/compat/ dir.
- support config operations for EXOS-based platforms
- add regex to detect command failure responses
- add exos action plugin for "backup" operation
- add unit tests for exos_command (currently 94% coverage of
exos_config.py)