[FrontEnd][Tech Debt] Structure improvements

[popovycholeg]

1. All folders in the components folder should follow the same naming pattern. Start with an uppercase letter and use a camel case.
   CompanyCard - correct
   terms-and-conditions-app - to improve.
2. Move component tests from src/tests to component folders.
   src/tests/CompanyCard.test.js => FrontEnd/src/components/CompanyCard.test.js
   We can use the src/tests folder for the integration tests.
3. Define entry points of React pages in the pages folder. so
4. Define navigation logic for the client and admin app in the routes folder.