[Feature] Create new branch "practice" for practice

[fnabinash]

The main branch contains all the solutions.

It will be helpful if you create a new branch questions or something that contains only files with the hello_world program then anyone who wants to practice can solve those to practice all the exercises.

meaning, all the workspaces with all members in it but the main.rs only contains the hello_world program.

Also, add the problem statement at the top of every main.rs file for convenience.

[fnabinash]

Created the practice branch, so that anyone can fork the repo can practice on their own and can track their own progress.

Check out here -> https://github.com/fnabinash/rust-practice/tree/practice