Refactor the code according to DR code review

[IradDoron]

1. Delete unused packages and files.
2. Delete global variables, functions and types and put them where they been used.
3. Initilaized MUI.
4. Rename the "services" directory to "dbActions" and put it in the "lib" directory.
5. Move all the REST endpoints from "controllers" to "api".
6. Use Zustand to handle state management where needed.
7. Hide all content that not related to MVP with some "future flag".
8. Remove the Accessibility button from the navbar (keep it in the project for the future).
9. Move the "models" and "mockData" directory to a directory named "db" inside "lib".
10. Update to next-auth 5 beta.
11. Delete Tailwind, Styled Components and Stylex.