✨(email) white brand email

The email was branded "La Suite Numérique",
we updated the template to make it generic, we
will use settings env variables to customize the
email for each brand.

src/mail/mjml/invitation.mjml

@@ -3,19 +3,14 @@
 
   <mj-body mj-class="bg--blue-100">
     <mj-wrapper css-class="wrapper" padding="0 25px 0px 25px">
-      <mj-section
-        background-url="{{domain}}/assets/mail-header-background.png"
-        background-size="cover"
-        background-repeat="no-repeat"
-        background-position="0 -30px"
-      >
+      <mj-section css-class="wrapper-logo">
         <mj-column>
           <mj-image
             align="center"
-            src="{{domain}}/assets/logo-suite-numerique.png"
-            width="250px"
+            src="{{logo_img}}"
+            width="320px"
             align="left"
-            alt="{%trans 'La Suite Numérique' %}"
+            alt="{%trans 'Logo email' %}"
           />
         </mj-column>
       </mj-section>
@@ -51,7 +46,11 @@
           </mj-text>
           <!-- Signature -->
           <mj-text>
-            <p>{% trans "Brought to you by La Suite Numérique" %}</p>
+            <p>
+              {% blocktrans %}
+                Brought to you by {{brandname}}
+              {% endblocktrans %}
+            </p>
           </mj-text>
         </mj-column>
       </mj-section>