Redirect service_templates.md to integrations doc

Service templates are removed in 14.0. This commit
adds the doc redirect.

doc/user/project/integrations/services_templates.md

 ---
-stage: Create
-group: Ecosystem
-info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
+redirect_to: '../../admin_area/settings/project_integration_management.md'
+remove_date: '2021-09-09'
 ---
 
-# Service templates **(FREE)**
+This document was moved to [another location](../../admin_area/settings/project_integration_management.md).
 
-WARNING:
-Service templates were [removed](https://gitlab.com/gitlab-org/gitlab/-/issues/268032)
-in GitLab 14.0. Use [project integration management](#central-administration-of-project-integrations) instead.
-
-Using a service template, GitLab administrators can:
-
-- Provide default values for configuring integrations when creating new projects.
-- Bulk configure all existing projects in one step.
-
-When you enable a service template:
-
-- The defaults are applied to **all** existing projects that either:
-  - Don't already have the integration enabled.
-  - Don't have custom values stored for already enabled integrations.
-- Values are populated on each project's configuration page for the applicable
-  integration.
-- Settings are stored at the project level.
-
-If you disable the template:
-
-- GitLab default values again become the default values for integrations on
-  new projects.
-- Projects previously configured using the template continue to use those settings.
-
-If you change the template, the revised values are applied to new projects. This feature
-does not provide central administration of integration settings.
-
-## Central administration of project integrations
-
-A new set of features is being introduced in GitLab to provide more control over
-how integrations are configured at the instance, group, and project level. For
-more information, read more about:
-
-- [Setting up project integration management](../../admin_area/settings/project_integration_management.md) (introduced in GitLab 13.3)
-- [Our plans for managing integrations](https://gitlab.com/groups/gitlab-org/-/epics/2137).
-
-## Enable a service template
-
-Navigate to the **Admin Area > Service Templates** and choose the service
-template you wish to create.
-
-Recommendation:
-
-- Test the settings on some projects individually before enabling a template.
-- Copy the working settings from a project to the template.
-
-There is no "Test settings" option when enabling templates. If the settings do not work,
-these incorrect settings are applied to all existing projects that do not already have
-the integration configured. Fixing the integration then needs to be done project-by-project.
-
-## Service for external issue trackers
-
-The following image shows an example service template for Redmine.
-
-![Redmine service template](img/services_templates_redmine_example.png)
-
-For each project, you still need to configure the issue tracking
-URLs by replacing `:issues_tracker_id` in the above screenshot with the ID used
-by your external issue tracker.
+<!-- This redirect file can be deleted after <2021-09-09>. -->
+<!-- Before deletion, see: https://docs.gitlab.com/ee/development/documentation/#move-or-rename-a-page -->