adds BMC proxy feature.

This patch simply allows foreman to save a proxy with BMC feature.

without this, Foreman will error out and the proxy won't be usable at all.

refs #832 do not force smartvars order saved if they are the default or not sent over the wire.

• fix user documentation
• remove password_confirmation from user api
• Add json template for users#create

fixes #1878 - Double quote in the wrong place included invalid kernel boot option

refs #832 - making sure that ENC values cast - skipped this patch somehow

fixes #832 - adds parameterized class support

Credits:
This patch is based on the original work of Olivier Favre
<olivier@yakaz.com> many many thanks!

• import class parameters, and try to understand their types
• support a complex matrix of environments, puppet classes and their...

fixed deprecation warning.

ensure yaml UI output is formatted correctly

fixes #1847 Ensure main and Settings aren't shown on the puppetclasses page linked to from the host page

fixes #1825 - unable to select an openstack image.

Note that probably Fog 1.5 is required for this to work.