Documentation

- Update **README.md** mentioning about what the project is, and how to use it.
- Add **CONTRIBUTING.md** explaining the contributing process. Example: [Power Menu CONTRIBUTING.md](https://github.com/abhiyandhakal/power-menu/blob/master/CONTRIBUTING.md)
- Add **CODE_OF_CONDUCT.md** to maintain the order in the community. Example: [Power Menu CODE_OF_CONDUCT.md](https://github.com/abhiyandhakal/power-menu/blob/master/CODE_OF_CONDUCT.md)

Review the repository and the requested documentation files: README.md, CONTRIBUTING.md, and CODE_OF_CONDUCT.md. Update README.md with the project's purpose and usage, add the contributing process and community guidelines, and consider the linked Power Menu examples; the work is done when all three documents are present and cover the requested topics.

Written by the indexing model from the issue text.