FEAT #13998 TIME 3 begin input registered mail

...l/issuing-site/indexing/issuing-site-input.component.html

...l/issuing-site/indexing/issuing-site-input.component.scss

...ail/issuing-site/indexing/issuing-site-input.component.ts

src/frontend/app/document-form.module.ts

...app/indexation/indexing-form/indexing-form.component.html

...d/app/indexation/indexing-form/indexing-form.component.ts

src/lang/lang-fr.json