add tree view option

[iignatevich]

No description provided.

[davidferlay]

This case looks good:

➜ ./plasmactl dependencies interaction/services/roles/mail_postfix  
- Parent dependencies:
interaction/applications/roles/mail
- Child dependencies:
interaction/softwares/roles/postfix
interaction/softwares/roles/postfix_ldap
platform/softwares/roles/alpine

➜ ./plasmactl dependencies interaction/services/roles/mail_postfix --tree
- Parent dependencies:
interaction__services__mail_postfix
└── interaction/applications/roles/mail
- Child dependencies:
interaction__services__mail_postfix
└── interaction/softwares/roles/postfix_ldap
    └── interaction/softwares/roles/postfix
        └── platform/softwares/roles/alpine

But this case is listing itself only as parent dependency :

➜ ./plasmactl dependencies platform/libraries/roles/executor --tree
- Parent dependencies:                                  
platform__libraries__executor
- Child dependencies:
platform__libraries__executor
├── integration/libraries/roles/errors
├── integration/libraries/roles/loopback
│   ├── integration/libraries/roles/metrics
│   │   ├── platform/libraries/roles/configuration
│   │   │   └── platform/libraries/roles/log
│   │   └── platform/libraries/roles/log
│   ├── platform/libraries/roles/event
│   │   ├── integration/libraries/roles/errors
│   │   └── platform/libraries/roles/log
...

whereas it does not appear without --tree option:

➜  build git:(master) ./plasmactl dependencies platform/libraries/roles/executor       
- Child dependencies:
integration/libraries/roles/changelog
integration/libraries/roles/criteria
integration/libraries/roles/errors
integration/libraries/roles/loopback
integration/libraries/roles/metrics
integration/libraries/roles/revision
integration/libraries/roles/utils
platform/libraries/roles/configuration
platform/libraries/roles/event
platform/libraries/roles/flow
platform/libraries/roles/function
platform/libraries/roles/log
platform/libraries/roles/skill
platform/libraries/roles/transport

• I guess with --tree target resource should be excluded if it does not list any further parent/child dependency

Also, target resource appears as mrn whereas --mrn option is not used

./plasmactl dependencies platform/libraries/roles/executor --tree
- Parent dependencies:                                  
platform__libraries__executor
- Child dependencies:
platform__libraries__executor
├── integration/libraries/roles/errors

Other resources in tree are listed in expected format