Heat: Added optional components to nova/neutron controller

This patch will add the support for heat cloudformation and for
heat cloudwatch in the foreman installation based on the boolean
variables $heat_cfn and $heat_cloudformation that when set to true,
will install the components.
Change optional Heat parts params from CHANGEME to false

Also remove trailing comma that caused syntax error.
heat_controller puppet class to reduce code duplication

Move common Heat code from Neutron-based and Nova-Network-based
controller classes to a common class which is then included.
Use str2bool for vars in Heat optional part conditionals
Fix typo in included class name
Merge pull request #16 from jistr/heat_optional_services

Heat optional services