✨(auth) add silent login

Currently users already logged in to the SSO have to click on
the login button again to be connected.
This extra step should not be necessary.

This commit uses the "silent=true" parameter to the login
endpoint to avoid the extra step.

src/backend/impress/settings.py

@@ -549,6 +549,16 @@ class Base(Configuration):
     SESSION_COOKIE_NAME = "docs_sessionid"
 
     # OIDC - Authorization Code Flow
+    OIDC_AUTHENTICATE_CLASS = values.Value(
+        "lasuite.oidc_login.views.OIDCAuthenticationRequestView",
+        environ_name="OIDC_AUTHENTICATE_CLASS",
+        environ_prefix=None,
+    )
+    OIDC_CALLBACK_CLASS = values.Value(
+        "lasuite.oidc_login.views.OIDCAuthenticationCallbackView",
+        environ_name="OIDC_CALLBACK_CLASS",
+        environ_prefix=None,
+    )
     OIDC_CREATE_USER = values.BooleanValue(
         default=True,
         environ_name="OIDC_CREATE_USER",