OpenAPI loader (generator) for models

[naturallymitchell]

to make REST API Command Line Clients work, in general. https://github.com/foundpatterns/torchbear/issues/231

should be in a theme? should be in a package? should be in a theme in a package? #143

template variables have to be given using a script. scripting should take place in actions>?>.. ...it should be set up to happen using packaged events whose actions get triggered based on rules and should be organized in modules that an action "overall" puts into template variables

overall means that whatever functionality it should be doing should not be something that can be refactored into torchbear bindings. it should be something that can only simply be done in a script (in an extreme sense??)