Enforce always adding HardwareOptions to HardwareCompilationConfig

Explanation of changes

• Makes HardwareOptions required field in the HardwareCompilationConfig. (zero hardware options are still supported, because all hw options fields are optional; all a user has to do is add a "hardware_options": {} to the hardware compilation config input dictionary).
• Allows omitting "frequency" key in LO settings Qblox backend to avoid unclear KeyError (#446 (closed)).

The below code now no longer raises a "frequency" KeyError (see #446 (closed)), but an ValidationError that the HardwareOptions are missing.

def test_unclear_error(
    mock_setup_basic_transmon_with_standard_params,
    hardware_compilation_config_qblox_example,
):
    hardware_config = hardware_compilation_config_qblox_example
    mock_setup = mock_setup_basic_transmon_with_standard_params
    quantum_device = mock_setup["quantum_device"]

    del hardware_config["hardware_options"]
    quantum_device.hardware_config(hardware_config)

    qubit = mock_setup["q0"]

    schedule = Schedule("frequency valueerror")
    schedule.add(Measure(qubit.name))

    compiler = SerialCompiler("compiler", quantum_device=quantum_device)
    compiled_schedule = compiler.compile(schedule)

Motivation of changes

Closes #446 (closed)

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