Handle connected mode in contact form

src/app/core/components/contact/contact.component.html

src/app/core/components/contact/contact.component.scss

src/app/core/components/contact/contact.component.spec.ts

src/app/core/components/contact/contact.component.ts

src/app/core/components/header/header.component.spec.ts

src/app/core/components/header/header.component.ts

src/app/core/components/login/login.component.spec.ts

src/app/core/models/auth.model.ts

src/app/core/services/auth.service.ts

src/i18n/messages.en.xlf

src/i18n/messages.fr.xlf