Add a11y tools

[Verthon]

• add automated check for a11y
• Cypress-Axe and axe-core
• add it to current github-pipelines to validate on mr
  Eg.

import { mount } from '@cypress/react'; // For component tests
import 'cypress-axe';

it('Should have no accessibility violations', () => {
  mount(<YourComponent />);
  cy.injectAxe(); // Injects the axe-core library
  cy.checkA11y(); // Checks for accessibility violations
});