improve README examples of stats/base/dists/poisson namespace

[nishant-s7]

Resolves #1641

Description

What is the purpose of this pull request?

This pull request:

• Add examples of the functions present in stats/base/dists/poisson namespace and their usage.
• Adds example demonstration using 7 functions in the README.
• Adds the same demonstration example in examples/index.js

Related Issues

Does this pull request have any related issues?

This pull request:

• resolves [RFC]: improve README examples of stats/base/dists/poisson namespace #1641

Questions

Any questions for reviewers of this pull request?

No.

Other

Any other information relevant to this pull request? This may include screenshots, references, and/or implementation notes.

I've created a real-life use case to make it more interesting, which utilizes some commonly used functions of poisson distribution.

Checklist

Please ensure the following tasks are completed before submitting this pull request.

• Read, understood, and followed the contributing guidelines.

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@stdlib-js/reviewers

[stdlib-bot]

👋 Hi there! 👋

And thank you for opening your first pull request! We will review it shortly. 🏃 💨

[Planeshifter]

Thanks @nishant-s7 for your PR! Looks good, just keep in mind that per our style conventions we do not include a space in console annotations, so e.g. // => ~ 3.12 should be // => ~3.12.

Will merge once CI has passed.