Add support for the evaluate keyword

The evaluate keyword is to be combined with the where clause. This evaluates the condition encompassed against the scope specified in the where clause. See [Evaluate documentation](https://github.com/Azure/template-analyzer/blob/main/docs/authoring-json-rules.md#evaluate-) for more details

## Example
``` javascript
{
"evaluate": {
"resourceType": "Microsoft.Compute/virtualMachines",
"path": "properties.osProfile.adminPassword",
"hasValue": false // Evaluates to `true`
} // Evaluates to the same as the inner evaluation (`true`)
}
```