Add a new python project [bank interest calculator]

[ninja-noodle]

Add my project 'Bank Interest Calculator' as a contribution

New files -> interest_calculator.py, README.md

README features -> a description of what the program is & how the program works, ways to execute and use the script

Features -> The script can calculate the total amount of interest 'or' the total amount of your savings including the interest according to how many years and how much yearly the user will save and the specific percentage(eg 0.1or 10) of interest.