Allow shorthand in `create-policy` command

Create Policy is a representative example of the shorthand involved. This converts create-policy attributes `repo`, `task`, `broker`, and `tags` to no longer need an object/hash with just the "name" property defined. In order to preserve backward-compatibility, this command now overrides `conform!`. The method upgrades commands written in the old syntax to the new syntax.

There was a previous regression where create-policy would not create tags that specified a `rule` array. This has been added back.
Shorthand references in other commands

`create-repo` and `move-policy` need the same updates for references from just a string rather than the string in an object's `name` property.

This was a good opportunity to fix up and refine the spec tests for both commands.

Fixes https://tickets.puppetlabs.com/browse/RAZOR-192