ESLint & Prettier - configure verification of code quality

[BartoszKlonowski]

The goal of this issue is to provide the application with code quality verification.

The main features of this should be to:

• configure eslint to work with notes app
• configure prettier through eslint to work with notes app
• add pre-commit/pre-push hook and run linter there

For ESLint the eslint-config-callstack should be used
(this will make the job easier and ensure the same standard for each product/app is remained).

For Prettier the best would be to once again refer to Prettier section in the Onboarding docs.
There's also a "Use ESLint to run Prettier" section, which might me useful as well!

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NOTE: The best would be to launch the verification in the CI (for example the same way as it was done in the keep-your-session private project in PR#5) and as a pre-commit.