test(webapp): provide tests in CI

- add url and page as env variables to choice where to test and update the others
- To pass a variable to a job's service, they have to be declared in the "variables" global -> doesn't work (see: [#37])
- use of the deployed image to do E2E test instead of services of gitlab

web-app/cypress.config.ts

@@ -5,5 +5,9 @@ export default defineConfig({
     setupNodeEvents(on, config) {
       // implement node event listeners here
     },
+    specPattern: [
+      "cypress/e2e/*.cy.{js,jsx,ts,tsx}",
+      "cypress/unit/*.cy.{js,jsx,ts,tsx}",
+    ],
   },
 });