Add Fencing support

...by overriding Foreman views and controllers.
The following files are copied over from Foreman and modified for the specific use-case:
- app/assets/javascripts/staypuft/host_edit.js
- app/views/hosts/_form.html.erb
- app/views/hosts/_unattended.html.erb
For these params, it looks like the 'safe mode rendering' bits are missing. From a quick look, I'm not sure that the  whitelist in 'class Jail < Safemode::Jail' for these models includes bmc_nic, etc.