Change detection and check mode fixes for apt_key
* allow apt-key to use proxies
* add note about deprecation of apt-key itself
* expanded error msgs
* show all keys
* fix short_format parsing
* added more return info and documented it
* Add explicit apt tests for fnmatch and update_cache
* Add explicit apt_key tests for fetching key directly from url
* ci_complete ci_coverage
* Remove repo only by repo
* ci_complete ci_coverage
* Add apt cache update after apt_repository to show that the cache doesn't update
* ci_complete ci_coverage
* Add systemd tests for enabling and disabling a service
* ci_complete ci_coverage
* Remove incidental_zabbix_host
* ci_complete ci_coverage
A preliminary set of test targets for "core" supported module that had no independent tests. These will also help us ensure python3 compatibility for those modules and prevent future regressions.
