<!--- 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 -->

),
            location=dict(
                type='str',
                updatable=False,
                disposition='/',
                comparison='location'
            ),
            publishing_profile=dict(
                type='dict',
                disposition='/properties/publishingProfile',
                options=dict(
                    target_regions=dict(
                        type='list',
                        disposition='targetRegions',
                        options=dict(
                            name=dict(
                                type='str',
                                required=True,
                                comparison='location'
                            ),
                            regional_replica_count=dict(
                                type='int',
                                disposition='regionalReplicaCount'
                            ),
                            storage_account_type=dict(
                                type='str',
                                disposition='storageAccountType'
                            )
                        )
                    ),