<!--- 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 -->
azure_rm_galleryimageversion_module should be able to take data disk snapshots as input.

##### ISSUE TYPE
- Feature Idea

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->
azure_rm_galleryimageversion_module

##### ADDITIONAL INFORMATION
<!--- Describe how the feature would be used, why it is needed and what it would solve -->
Starting from SIG api version 2019-07-01, we support creating image version from snapshots, which contains 1 os disk snapshot and 0 to many data disk snapshots. By having this feature, it give customers full power to create image version from snapshots.

Here is a sample request entity:
{"name":"1.0.0","location":"West US","properties":{"publishingProfile":{"excludeFromLatest":false},"storageProfile":{"osDiskImage":{"source":{"id":"/subscriptions/<subId>/resourceGroups/rgName/providers/Microsoft.Compute/snapshots/osSnapshotName"}},"dataDiskImages":[{"lun":0,"source":{"id":"/subscriptions/<subId>/resourceGroups/rg/providers/Microsoft.Compute/snapshots/datadiskSnapshot1"}}]}}}

So for data disk, user needs to provide "lun" and "source".

<!--- Paste example playbooks or commands between quotes below -->
```yaml

```

<!--- HINT: You can also paste gist.github.com links for larger files -->

'Standard_ZRS']
                    )
                )
            ),
            state=dict(
                type='str',
                default='present',
                choices=['present', 'absent']
            )
        )
        self.resource_group = None
        self.gallery_name = None
        self.gallery_image_name = None
        self.name = None
        self.gallery_image_version = None
        self.results = dict(changed=False)
        self.mgmt_client = None
        self.state = None
        self.url = None
        self.status_code = [200, 201, 202]
        self.to_do = Actions.NoAction
        self.body = {}
        self.query_parameters = {}
        self.query_parameters['api-version'] = '2019-07-01'
        self.header_parameters = {}
        self.header_parameters['Content-Type'] = 'application/json; charset=utf-8'
        super(AzureRMGalleryImageVersions, self).__init__(derived_arg_spec=self.module_arg_spec,
                                                          supports_check_mode=True,
                                                          supports_tags=True)
    def exec_module(self, **kwargs):