tree command, reimplementation of `doctrine:phpcr:node:dump` command

Also influenced by linux `tree` command, e.g. output like

````
$ tree -L 2                                                                                                              ◼
.
├── bin
│   └── phpcrsh
├── box.json
├── CHANGELOG.md
├── composer.json
├── composer.lock
├── features
│   ├── bootstrap
│   ├── fixtures
│   ├── phpcr_access_control_privilege_list.feature
````