Suggestion: Add optimization functions, ml algorithms under `machine_learning` folder

I would like to suggest adding Optimization functions, machine learning and deep learning algorithms in this repository. This can be added in a separate folder called machine_learning folder. Further, this folder can contain various algorithms that are used in machine learning and deep learning.

Initially, these Optimization functions can be added under machine_learning/optimization/

• Gradient Descent
• Stochastic Gradient Descent (SGD)
• Mini-Batch Gradient Descent
• Adam (Adaptive Moment Estimation)
• RMSprop (Root Mean Square Propagation)
• AdaGrad (Adaptive Gradient Algorithm)

And these in machine_learning/

• Linear Regression
• Logistic Regression
• Decision Trees
• Random Forest
• Support Vector Machines (SVM)
• K-Nearest Neighbors (K-NN)
• Naive Bayes
• K-Means Clustering
• Principal Component Analysis (PCA)