Foreman Maintain

Add --whitelist option

Allows to mark some steps to be ignored in the results: allows to
continue even when some checks are failing.

Assumeyes option

RFE #23 - Add new status [WARNING] - Check: is system self registered

Add tests for tasks paused check and additional procedures

Check count of paused tasks and offer next steps

Fixes #3 - Add option to skip the prompted step

Make the spinner opt-in, not opt-out

The default spinner caused issues when one needs to interact with the
user (printing additional messages). As it's needed only for long
running actions, it should not be enforced by default.

Refactor the choice of next steps

Tests for runner and reporter