PLT-4524 Update password reset page (#4522)

* Implement PLT-4524 Update password reset page

* fix lints

* changes based on review

* update per request/review

* update tests

* add css for alert-success

* change per request

api/user.go

@@ -1723,7 +1723,7 @@ func sendPasswordReset(c *Context, w http.ResponseWriter, r *http.Request) {
 
 	var user *model.User
 	if result := <-Srv.Store.User().GetByEmail(email); result.Err != nil {
-		c.Err = model.NewLocAppError("sendPasswordReset", "api.user.send_password_reset.find.app_error", nil, "email="+email)
+		w.Write([]byte(model.MapToJson(props)))
 		return
 	} else {
 		user = result.Data.(*model.User)