Introduce module based structure to the codebase

[suramrit]

This code base was written 2 years ago while still learning golang.

Almost all the implementations have package structure to them.

Here is a general plan of action that you can take:

• take up one related topic (eg - concurrency)
• take the files in the repo related to concurrency
• create a package for concurrency
• [Optional] Add test files for the package

For any details on code organization in go, please check : https://golang.org/doc/code.html

Please feel free to add any suggestions and topics for the repo. Happy Hacktobering!

[suramrit]

• Completed Package "concurrency"