API: Allow to send activation email when creating customers (#2729)

Co-authored-by: Raphael Michel <michel@rami.io>

doc/api/resources/customers.rst

@@ -131,7 +131,9 @@ Endpoints
 
 .. http:post:: /api/v1/organizers/(organizer)/customers/
 
-   Creates a new customer
+   Creates a new customer. In addition to the fields defined on the resource, you can pass the field ``send_email``
+   to control whether the system should send an account activation email with a password reset link (defaults to
+   ``false``).
 
    **Example request**:
 
@@ -143,7 +145,8 @@ Endpoints
       Content-Type: application/json
 
       {
-        "email": "test@example.org"
+        "email": "test@example.org",
+        "send_email": true
       }
 
    **Example response**: