FEAT #8489 sendmail param form + var lang

apps/maarch_entreprise/xml/services.xml

src/core/lang/lang-en.php

src/core/lang/lang-fr.php

src/core/lang/lang-nl.php

...istration/sendmail/sendmail-administration.component.html

...inistration/sendmail/sendmail-administration.component.ts

...tration/technical/technical-administration.component.html

...istration/technical/technical-administration.component.ts

src/frontend/lang/lang-en.ts

src/frontend/lang/lang-fr.ts

src/frontend/lang/lang-nl.ts