implemented insertion sort using javascript

This PR implements the code for Insertion Sort in JavaScript.

I have read the contributing guidelines in CONTRIBUTING.md and have ensured the following:

[x] My code is placed in the required directory as outlined in CONTRIBUTING.md
[x] My code file is named according to CONTRIBUTING.md
[x] Variables, classes, functions etc. follow camel case as outlined in CONTRIBUTING.md
[x] My code hasn't been implemented or claimed by someone else and I have checked the present issues and PRs for the same
[x] My code is well commented
[x] If my code is the first implementation of , I have added the link to this directory in README.md
[x] I have not copied my code from anywhere

deutranium / Algorithms