Add create_option to disk definitions (#62357)

Add create_option parameter to disk definitions to control whether disks
are created from the base image or are new disks being added to the VMs.
Currently, custom images with data disks defined in the image cannot be
used to launch VMs unless data disk definitions are excluded.  This
prevents the data disks from being modified/extended (like selecting a
different SKU or making the data disks bigger).  Exposing this option
allows VMSS VMs to be created with base images that have data disks
while extending their definitions.

Addresses #61804

lib/ansible/modules/cloud/azure/azure_rm_virtualmachinescaleset.py

@@ -151,6 +151,14 @@ options:
                     - ReadWrite
                 default: ReadOnly
                 version_added: "2.4"
+            create_option:
+                description:
+                    - Specify whether disk should be created Empty or FromImage.  This is required to allow custom
+                      images with data disks to be used.
+                choices:
+                    - Empty
+                    - FromImage
+                version_added: "2.10"
     virtual_network_resource_group:
         description:
             - When creating a virtual machine, if a specific virtual network from another resource group should be
@@ -345,6 +353,26 @@ EXAMPLES = '''
     managed_disk_type: Standard_LRS
     image: customimage001
 
+- name: Create a VMSS with a custom image and override data disk
+  azure_rm_virtualmachinescaleset:
+    resource_group: myResourceGroup
+    name: testvmss
+    vm_size: Standard_DS1_v2
+    capacity: 2
+    virtual_network_name: testvnet
+    upgrade_policy: Manual
+    subnet_name: testsubnet
+    admin_username: adminUser
+    admin_password: password01
+    managed_disk_type: Standard_LRS
+    image: customimage001
+    data_disks:
+      - lun: 0
+        disk_size_gb: 64
+        caching: ReadWrite
+        managed_disk_type: Standard_LRS
+        create_option: FromImage
+
 - name: Create a VMSS with over 100 instances
   azure_rm_virtualmachinescaleset:
     resource_group: myResourceGroup
@@ -963,7 +991,7 @@ class AzureRMVirtualMachineScaleSet(AzureRMModuleBase):
                             data_disks.append(self.compute_models.VirtualMachineScaleSetDataDisk(
                                 lun=data_disk.get('lun', None),
                                 caching=data_disk.get('caching', None),
-                                create_option=self.compute_models.DiskCreateOptionTypes.empty,
+                                create_option=data_disk.get('create_option', self.compute_models.DiskCreateOptionTypes.empty),
                                 disk_size_gb=data_disk.get('disk_size_gb', None),
                                 managed_disk=data_disk_managed_disk,
                             ))
@@ -1020,7 +1048,7 @@ class AzureRMVirtualMachineScaleSet(AzureRMModuleBase):
                             data_disks.append(self.compute_models.VirtualMachineScaleSetDataDisk(
                                 lun=data_disk['lun'],
                                 caching=data_disk['caching'],
-                                create_option=self.compute_models.DiskCreateOptionTypes.empty,
+                                create_option=data_disk.get('create_option', self.compute_models.DiskCreateOptionTypes.empty),
                                 disk_size_gb=data_disk['disk_size_gb'],
                                 managed_disk=self.compute_models.VirtualMachineScaleSetManagedDiskParameters(
                                     storage_account_type=data_disk.get('managed_disk_type', None)