add prequisities for anagram practice exercise

[AnishDe12020]

I have added the prerequisites for the anagram practice exercise. I am opening this pull request only for this exercise and as per how it goes I will decide on how many exercises I should add per pull request from next time.

References #984

[github-actions]

Dear AnishDe12020

Thank you for contributing to the JavaScript track on Exercism! 💙
You will see some automated feedback below 🤖. It would be great if you can make sure your PR covers those points. This will save your reviewer some time and your change can be merged quicker.

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_{Automated comment created by PR Commenter 🤖.}

[junedev]

@AnishDe12020 The CI checks complain about the formatting. Here you can find out how to format the content correctly: https://github.com/exercism/javascript/blob/main/CONTRIBUTING.md#format

[AnishDe12020]

@AnishDe12020 The CI checks complain about the formatting. Here you can find out how to format the content correctly: https://github.com/exercism/javascript/blob/main/CONTRIBUTING.md#format

Ya sure, I have run the script to format. Just one recommendation, running prettier can be added as a script to package.json so that it can easily be run with a comment like npm run format.