* Change role argspec file used by ansible-doc
This changes the file used for role argument specs from meta/argument_specs.yml
to meta/main.yml. The argument specs are expected to be in that file under the
top-level entry of `argument_spec`.
* Switch to argument_specs
* Support listing roles in text and JSON
* Change tests for unfrack'd playbook_dir var
These tests were using '/tmp' for testing the setting of the playbook_dir
var. Now that we unfrack that var, MacOS will change this to '/private/tmp'
causing the tests to fail. We can choose a path that does not exist (since
unfrack does not validate existence) so that we can guarantee unfracking
will not change the value.
