* First version of working script to download the GLDv2 dataset

* First version of the DEFL package installation script

* First working version of the DELF package installation script

* Fixed feedback from PR review

* Push to Github of changes to the TFRecord data generation script for DELF.

* Merged commit includes the following changes:
315363544  by Andre Araujo:

    Added the generation of TRAIN and VALIDATE splits from the train dataset.

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314676530  by Andre Araujo:

    Updated script to download GLDv2 images for DELF training.

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314101235  by Andre Araujo:

    Added newly created module 'utils' to the copybara script.

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313677085  by Andre Araujo:

    Code migration from TF1 to TF2 for:
    - logging (replaced usage of tf.compat.v1.logging.info)
    - testing directories (replaced usage of tf.compat.v1.test.get_temp_dir())
    - feature/object extraction scripts (replaced usage of tf.compat.v1.train.string_input_producer and tf.compat.v1.train.start_queue_runners with PIL)

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312770828  by Andre Araujo:

    Internal change.

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PiperOrigin-RevId: 315363544

* First version of the updated README of the DELF training instructions

* Added to the README the section describing the generation of the training data

* Added warning about the TFRecord generation time

* Updated the launch of the training

* Minor README update

* Integrated review feedback
Co-authored-by: NAndre Araujo <andrearaujo@google.com>