[Algo] Selection Sort [Python]

[de-sh]

Going through the repo I couldn't find an algorithm implemented for selection sort in python.
I have created a pull request for the same.

[sangamcse]

GitMate.io thinks possibly related issues are #305 ([Algo] Add Knapsack problem [Python]), #238 ([Algo] Coin Change Problem [Python]), #43 ([Algo] Binary Search [Python]), #14 ([Algo]: Add Heapsort in Python), and #302 ([Algo] Add Python Bubble Sort).