Add 'tree' command to Hypernode Deploy to get overview and list of tasks for a stage

[poespas]

Example output:

» hypernode-deploy tree deploy     
The task-tree for deploy:
├── slack:notify  // before deploy
└── deploy
    ├── deploy:upload
    │   ├── prepare:ssh
    │   ├── deploy:info
    │   ├── deploy:prepare
    │   │   ├── deploy:info
    │   │   ├── deploy:setup
    │   │   ├── deploy:lock
    │   │   ├── deploy:release
    │   │   ├── deploy:shared
    │   │   └── deploy:writable
    │   ├── deploy:copy
    │   │   ├── deploy:copy:code
    │   │   └── deploy:shared
    │   └── deploy:deploy
    ├── deploy:link
    │   ├── deploy:symlink
    │   ├── cachetool:clear:opcache  // after deploy:symlink
    │   ├── cachetool:cleanup  // after cachetool:clear:opcache
    │   └── deploy:public_link
    └── deploy:finalize
        ├── deploy:after
        ├── deploy:unlock
        ├── deploy:cleanup
        └── deploy:success
        └── slack:notify:success  // after deploy:success