Adding Remove and Update Tag Functions

* Created a delete-tag command.
* Created an update-tag-rule command allowing an in place replacement of
  the matcher on a tag.
* When creating or updating a tag, it will be immediately evaled against
  each node and applied/removed as appropriate.
* Updated api docs
Eval_nodes() will now be run async

 - When creating or updating a tag. A background task will fire to
   test tag against all nodes and apply/remove as appropriate.
Implementing force for delete/update tag

 - Require the force option to be true if manipulating a tag that is
   associated with a policy.
Adding tests to match changes