This adds the ability to exempt a controller from all checks similar to
the annotation for "exempt" which exempts all checks.
I added the tests to go with this as well as for the IsActionable
function.
* first pass at adding exemptions
* Update config.yaml
* make config_test more reliable
* add flag to disallow exemptions in dashboard
* add disallow-exemptions flag to CLI
* add comments
* fix exemptions flag
* fix alert on dashboard
* minor style changes