Export and Import from a single YAML file

@Fryguy @gmcculloug @chessbyte @tinaafitz 
For export and import of automate models we have 3 ways to store the data based on YAML. We currently have (1) ZIP file that can store all the YAML's or (2) store all the YAML's in a directory. This PR adds a 3rd one which is to have all the model into a single consolidated YAML. The single consolidated YAML helps us with our specs where we don't have to store all the model YAML files separately in a directory.
This should be cleaned up so subsequent runs aren't tainted.  Another option is to stub the File.exist? method (or whatever it is that is being accessed) to return true, which may be a better approach