Add support for Caltech-UCSD Birds-200-2011 dataset

[shakeebmurtaza]

🚀 Feature

I want to add support for Caltech-UCSD Birds-200-2011 dataset in torchvision.datasets.

Motivation and Pitch

A lot of people are using Caltech-UCSD Birds-200-2011 dataset for the evaluation of their proposed models. According to paperswithcode.com 787 papers employed this dataset since 2017 and these numbers are growing. So, I want to add support for this data in the datasets library.

cc @fmassa @vfdev-5 @pmeier

[vadimkantorov]

I had an early stab in #147, but never finished it :(

[shakeebmurtaza]

I created a pull request with respect to your previous issue #147.

[xiaoyuan0203]

Can this issue be closed because of #5154 ?