<!--- Verify first that your feature was not already discussed on GitHub -->
<!--- Complete *all* sections as described, this form is processed automatically -->

##### SUMMARY
<!--- Describe the new feature/improvement briefly below -->
Ansible by default only creates LUKS1 format devices. Considering LUKS2 extra features and age, I think it would be beneficial to allow users to create LUKS2 devices.

##### ISSUE TYPE
- Feature Idea

##### COMPONENT NAME
luks_device

##### ADDITIONAL INFORMATION
<!--- Describe how the feature would be used, why it is needed and what it would solve -->
For reliability, one should use either disk UUID's or labels. UUID's are (in my opinion) a hassle when it comes to using them in Ansible.

Enter labels. Labels can be the same across multiple hosts, and will be tied to the right disk/partition, even if sda1 suddenly becomes sdb1 after some hardware reconfiguration.

Now, the LUKS1 format, which Ansible creates by default with the `luks_device` module, does not support labels... Support was added with LUKS2.

It should be noted that, from what I can see, the module *does already support removing keys from LUKS2 format devices*.

<!--- Paste example playbooks or commands between quotes below -->
```yaml
- name: create LUKS2 container
  luks_device:
    device: "/dev/loop0"
    state: "present"
    keyfile: "/vault/keyfile"
    format: luks2
```
''' Returns the device that holds label passed by user
        '''
        self._blkid_bin = self._module.get_bin_path('blkid', True)
        label = self._module.params['label']
        if label is None:
            return None
        result = self._run_command([self._blkid_bin, '--label', label])
        if result[RETURN_CODE] != 0:
            return None
        return result[STDOUT].strip()
    def generate_luks_name(self, device):
        ''' Generate name for luks based on device UUID ('luks-<UUID>').
            Raises ValueError when obtaining of UUID fails.
        '''
        result = self._run_command([self._lsblk_bin, '-n', device, '-o', 'UUID'])
        if result[RETURN_CODE] != 0:
            raise ValueError('Error while generating LUKS name for %s: %s'
                             % (device, result[STDERR]))
        dev_uuid = result[STDOUT].strip()
        return 'luks-%s' % dev_uuid
class CryptHandler(Handler):
    def __init__(self, module):