Add support for EfficientNet

[xenova]

closes #638

Example usage:

import { pipeline } from '@xenova/transformers';

// Create image classification pipeline
const classifier = await pipeline('image-classification', 'chriamue/bird-species-classifier', {
    quantized: false,      // Quantized model doesn't work
    revision: 'refs/pr/1', // Needed until the model author merges the PR
});

// Classify an image
const url = 'https://upload.wikimedia.org/wikipedia/commons/7/73/Short_tailed_Albatross1.jpg';
const output = await classifier(url);
console.log(output)
// [{ label: 'ALBATROSS', score: 0.9999023079872131 }]

[HuggingFaceDocBuilderDev]

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