Added Evluation Metrics (F1, Confusion Matrix and AUC) to eval.py #169

[SakshamJain24]

Evaluation Metrics:

Added a confusion matrix, F1 score, and AUC (Area Under the Curve) to the evaluation.
Calculate and print these metrics after evaluating the model.
Replacements for Deprecated Methods:

Replace tf.flags with absl flags, including importing and defining flags using absl flags.
Remove tf.app.run() and use app.run(main) to parse the flags and run the main function.

Replacing contrib.learn.DNNClassifier:
Import the tf.estimator library.

These changes aimed to modernize the code for compatibility with TensorFlow 2.x and enhance the evaluation process with additional metrics.