Feature/subject in contact form (#1926)

* #1915 Add a subject to contact form and add it to email sent

* #1915 Add subject to contact form tests

* #1915 Contact form test corrected && tslint correction

shared/extra-utils/server/contact-form.ts

@@ -5,6 +5,7 @@ function sendContactForm (options: {
   url: string,
   fromEmail: string,
   fromName: string,
+  subject: string,
   body: string,
   expectedStatus?: number
 }) {
@@ -13,6 +14,7 @@ function sendContactForm (options: {
   const body: ContactForm = {
     fromEmail: options.fromEmail,
     fromName: options.fromName,
+    subject: options.subject,
     body: options.body
   }
   return request(options.url)