Command to init PHPCR

Command to init PHPCR (sulu:phpcr:init), it creates the default routes /cmf/routes , /cmf/contents:

- [ ] finish the code
- [ ] gather feedback for my changes
- [ ] submit changes to the documentation


| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| Tests pass?   | none
| Fixed tickets | none
| Doc           | [url to doc|none]