Auth: Add page to change password.

Configure launcher as a default return to address.

Use standard X-Forwarded-User instead of custom X-User header.
Add X-Forwarded-UserId header holding user unique identificator.

Change-Id: Ib2e6329ba9fb91d2cc9a86b0c5fc78898769e3b8
diff --git a/core/installer/welcome/dodo_app.go b/core/installer/welcome/dodo_app.go
index d71bf83..256007e 100644
--- a/core/installer/welcome/dodo_app.go
+++ b/core/installer/welcome/dodo_app.go
@@ -316,7 +316,7 @@
 }
 
 func (ug internalUserGetter) Get(r *http.Request) string {
-	return r.Header.Get("X-User")
+	return r.Header.Get("X-Forwarded-User")
 }
 
 func (ug internalUserGetter) Encode(w http.ResponseWriter, user string) error {