Manage Heat templates

[julienvey]

After many requests, I think we need to add heat support to the provider.

We could add in the configuration the following attributes

os.stacks = [{
  name: 'mystack',
  template: '/path/to/my/template.yml',             
  template_url: 'http://test.heat', 
  environment: '/path/to/my/environment.yml',
  environment_url: 'http://environment.heat',
  parameters: {
    router_id: '1234'
  }
}]

name and parameters should be optional

We should support multiple syntax, a single object or an array or even a single string which would be the template.

template_url and template should not be both allowed in a stack, it's one or the other

When vagrant up, we whould create the heat stacks, maybe update the stack when doing vagrant reload, and delete the stacks when doing vagrant destroy

We need to think of how to handle heat stack in the context of a multi-machines environment

[ggiamarchi]

At a first sight i would prefer to not consider the stack update. It could be a further issue.

[julienvey]

Sure, this is the high level feature, but we should definitively split the work into multiple (and more simple) issues

[julienvey]

I have started to work on a first implementation on this, should have a PR soon