### Summary

`ansible-inventory --graph` can be specified with a group though, the output is not a JSON format so that we cannot parse the output easily.

It would be helpful for us if the `ansible-inventory --list` could accept the group name.


### Issue Type

Feature Idea

### Component Name

inventory

### Additional Information

For example, I created an inventory file.

```
[groupA]
host1
host2
host3

[groupA:children]
groupA1

[groupB]
host11
host12

[groupC]
host21
host22
host23
host24

[groupC:children]
groupA1

[groupA1]
host101
host102
host103
host104
host105
```

Then I can get filtered output with `ansible-inventory --graph`.  It can catch all hosts in the child group as well.

```
$ ansible-inventory -i inventory --graph groupA
@groupA:
  |--@groupA1:
  |  |--host101
  |  |--host102
  |  |--host103
  |  |--host104
  |  |--host105
  |--host1
  |--host2
  |--host3
```

However `ansible-inventory --list` performs to output only for the whole hosts in the inventory.  We need the filtered output as the `--graph` in a JSON format.


### Code of Conduct

- [X] I agree to follow the Ansible Code of Conduct
INTERNAL_VARS = frozenset(['ansible_diff_mode',
                           'ansible_config_file',
                           'ansible_facts',
                           'ansible_forks',
                           'ansible_inventory_sources',
                           'ansible_limit',
                           'ansible_playbook_python',
                           'ansible_run_tags',
                           'ansible_skip_tags',
                           'ansible_verbosity',
                           'ansible_version',
                           'inventory_dir',
                           'inventory_file',
                           'inventory_hostname',
                           'inventory_hostname_short',
                           'groups',
                           'group_names',
                           'omit',
                           'playbook_dir', ])
class InventoryCLI(CLI):
    ''' used to display or dump the configured inventory as Ansible sees it '''
    name = 'ansible-inventory'
    ARGUMENTS = {'host': 'The name of a host to match in the inventory, relevant when using --list',
                 'group': 'The name of a group in the inventory, relevant when using --graph', }
    def __init__(self, args):
        super(InventoryCLI, self).__init__(args)
        self.vm = None
        self.loader = None
        self.inventory = None
    def init_parser(self):