Multi Region Support for Heat

The goal of this blueprint it to add multi region support for Heat. Right now Heat can orchestrate only one OpenStack installation (one region). We would like to use Heat to create/update and delete resources in different regions using one template file. It means that it should be possible to specify in template file for each resource in which region we want to create it. Multi region Heat engine should parse multi region template and using single Heat engines create all specified resources accordingly with dependencies.