[Refactor] Rename metrics

[ice-tong]

Motivation

We prefer that the names of Metric in MMEval follow the following two principles:

• Metric name is meaningful
• Unified Metric naming style

Modification

• Add deprecation warning
• SingleLabelMetric -> PrecisionRecallF1score (in PR [Refactor] Refactor single and multi label metrics #81 )
• MultiLabelMetric -> MultiLabelPrecisionRecallF1score (in PR [Refactor] Refactor single and multi label metrics #81 )
• COCODetectionMetric -> COCODetection
• F1Metric -> F1Score
• mmeval/metrics/f_metric.py -> mmeval/metrics/f1_score.py
• tests/test_metrics/test_f_metric.py -> tests/test_metrics/test_f1_score.py
• MAE -> MeanAbsoluteError
• MSE -> MeanSquaredError
• PSNR -> PeakSignalNoiseRatio
• SNR -> SignalNoiseRatio
• SSIM -> StructuralSimilarity
• SAD -> SumAbsoluteDifferences
• MattingMSE -> MattingMeanSquaredError

DeprecationWarning

Thanks to pep-0562, we can customize moudel's attribute access via __getattr__ to implement deprecation warnings.
We add a __geattr__ function into mmeval/__init__.py and mmeval/metrics/__init__.py.

_deprecated_msg = ...
__deprecated_metric_names__ = {
    'COCODetectionMetric': 'COCODetection',
    ...
}

def __getattr__(attr: str):
    if attr in __deprecated_metric_names__:
        message = _deprecated_msg.format(
            n1=attr, n2=__deprecated_metric_names__[attr])
        warnings.warn(message, DeprecationWarning, stacklevel=2)
        return globals()[__deprecated_metric_names__[attr]]
    raise AttributeError(f'module {__name__!r} has no attribute {attr!r}')