fixes #1183 - make an ESXi server appear in the UI without errors

Fixes #920 - Add authorization to hypervisor, bookmarks, subnets, smart-proxy/autosign and puppetca

Signed-off-by: Paul Kelly <paul.ian.kelly@googlemail.com>

fixes #922 - Confirmation message should be more explicit

fixes #843 - show more virtual guests information

added html view for guests
moved common methods into the virt plugin

fixes #835 - allow to delete virtual guests

added JSON output to guests
Added Guest model
Added confirmation before power cycle
Added Deletion option to guests

fixes #723 - Hypervisor details page

This also include basic functionality to power on/off guests