Delete specific routes with cisco.iosx.iosxr_static_routes

The functionality being asked for is the ability to update the deleted parameter to delete specific static routes instead of all routes under one afi or vrf. This change would provide customers with the flexibility to remove specific routes instead of all routes under afi or vrf. Currently if they want to remove routes created through the module, they need to manually remove them by logging into the device and running 'no <static route>'.