feat: add strip_email_domain to normalization of namespace

config-example.yaml

@@ -180,3 +180,9 @@ unix_socket_permission: "0770"
 #   client_id: "your-oidc-client-id"
 #   client_secret: "your-oidc-client-secret"
 #
+#   If `strip_email_domain` is set to `true`, the domain part of the username email address will be removed.
+#   This will transform `first-name.last-name@example.com` to the namespace `first-name.last-name`
+#   If `strip_email_domain` is set to `false` the domain part will NOT be removed resulting to the following
+#   namespace: `first-name.last-name.example.com`
+#
+#   strip_email_domain: true