fixes #1029 - allows smart variables to be resolved via http get request.

this would allow to an external query to resolve a variable value to a given host.

e.g.
http://foreman/hosts/<fqdn>/lookup_values/<variable_name>

fixes #322 Ability to add custom variables and multiple values resovled
in a dynamic Hierarchally order

This commits introduces the ability to define variables per puppet
class.

additionally, each class can have multiple values, depends on the host
which is requesting that variable....

splitted setting default data from the migration
this allows to add new data and modify its defaults
improved settings UI a bit more
refs #100