Clean up and standardize the way we handle Pulumi resource type creation

[brews]

At the moment we have a very basic functionin in rhg_pulumi_resources/gcp/infra.py, pulumi_type_name(). It relies on global variables set in the modules. It would be better to put it in a lower "utils" submodule with args already set for the package name.

The current setup isn't really a problem, but its easy to see how the current solution won't scale as this grows.