Add the ability to create VulnExceptions based on AssetGroups via the gem.

[razron]

With the addition of Vulnerability Exceptions at the Group level added to Nexpose it would greatly simplify how we currently have to grant/create exceptions for each asset in our groups now when use the Gem.

[sgreen-r7]

Thanks @razron -- we're working on it. We'll go ahead and leave this issue open for now, and update it once we have a better idea of the timeline when the feature will ship.

[sgreen-r7]

In an effort to get a better idea on a rollout timeline for this feature, I will reach out to the API engineering team and get their input. I will update this ticket again, once I get some more info.