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.
You don't need the proc literally here...just use a normal block...

```ruby
get_filenames_with_proc("#{parent_path}/#{METHOD_FOLDER_NAME}") do |item|
  item.ends_with?('.yaml')
end
```