Added command to re-class/ify/ documents

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | N/A
| Fixed tickets | N/A
| License       | MIT
| Doc PR        | N/A

Enable easy migration of classnames, updates both
phpcr:class and phpcr:parentclass fields.

Note is very little testing in this bundle, the tests that do exist are not travis aware and one of them requires a non-existing dev requirement (LiipFunctionalTestBundle).

This command should have a test to ensure that we don't get regressions when phpcr-utils changes, but this is difficult without serious bootstrapping.