General refactor

[msmaiaa]

• [x] Create shared types between the front and the backend
• [x] Add eslint and package to enforce conventional commits
• [x] Move the direct database access to custom models
• [x] Update admin/super admin verification middlewares on the back-end so that they can verify the user authentication instead of relying on requireAuth
• [x] Change folder structure, split code that can be shared and be independent