Add identity column to azure_kusto_cluster table closes #647

[misraved]

Integration test logs

Logs

``` Add passing integration test logs here ```

Example query results

Results

```sql select name, id, state from azure_kusto_cluster where identity ->> 'type' = 'SystemAssigned'; +--------------+------------------------------------------------------------------------------------------------------------------------------------------------+----------+ | name | id | state | +--------------+------------------------------------------------------------------------------------------------------------------------------------------------+----------+ | cluster-test | /subscriptions/11111111-f95f-4771-1111-111111111111/resourceGroups/kp-test-k8-compliance_group/providers/Microsoft.Kusto/Clusters/cluster-test | Creating | +--------------+------------------------------------------------------------------------------------------------------------------------------------------------+----------+ ```