Add formatting rules and linting to react-server code

[massi-ang]

Using standard code formatting and linting is important for several reasons:

1. Readability: Standard code formatting makes code more readable and understandable to other developers who may need to work with or maintain the code in the future. Consistent indentation, spacing, and formatting conventions help to structure the code in a way that is easy to follow.

2. Maintainability: Consistent code formatting makes it easier to identify and fix bugs, as well as make enhancements or modifications to the codebase. When code is formatted consistently, developers spend less time deciphering the code's structure and can focus more on its logic and functionality.

3. Collaboration: When multiple developers are working on the same project, adhering to a standard code formatting style ensures consistency across the codebase. This reduces confusion and misunderstandings among team members and promotes collaboration by making it easier to review, understand, and contribute to each other's code.

4. Code Reviews: Standard code formatting facilitates the code review process by providing a common baseline for evaluating code quality and style. Reviewers can focus on higher-level aspects of the code, such as logic correctness and performance, rather than getting bogged down in stylistic inconsistencies.

5. Tooling Support: Many integrated development environments (IDEs) and code editors offer built-in support for enforcing and automatically applying code formatting rules. By using standard formatting conventions, developers can take advantage of these tools to ensure that their code remains consistent and properly formatted throughout the development process.

6. Professionalism: Consistent code formatting reflects positively on the professionalism and attention to detail of the development team. It demonstrates a commitment to writing clean, maintainable code that is easy to understand and work with, which can contribute to the overall quality of the software product.

In summary, adhering to a standard code formatting style is essential for promoting readability, maintainability, collaboration, and professionalism in software development projects.

More info about linters and formatters can be found here

[ianarawjo]

Hey massi! Your PRs have been noted and I will look at them in detail when I have a good moment of free time.

[massi-ang]

Thanks. As I wrote in the 2 PRs:

1. Look at #222 first and merge it. This PR is only about code formatting, and the result can be easily reproduced by running prettier with the committed configuration
2. After #222 has been merged, #223 will show a more reasonable diff. The changes made are the minimal ones so that eslint passes with the given configuration.