Remove PropagateServiceTemplateWorker and queue

Deleted the PropagateServiceTemplateWorker and removed references to it
in the all_queues YAML file as well as the Sidekiq worker spec.

As part of the worker removal, we're adding a post deploy clean up
migration to clear any pending jobs that could be on the queue.

Changelog: other

app/workers/all_queues.yml

@@ -2717,15 +2717,6 @@
   :weight: 1
   :idempotent: true
   :tags: []
-- :name: propagate_service_template
-  :worker_name: PropagateServiceTemplateWorker
-  :feature_category: :integrations
-  :has_external_dependencies:
-  :urgency: :low
-  :resource_boundary: :unknown
-  :weight: 1
-  :idempotent:
-  :tags: []
 - :name: reactive_caching
   :worker_name: ReactiveCachingWorker
   :feature_category: :not_owned

app/workers/propagate_service_template_worker.rb

-# frozen_string_literal: true
-
-# No longer in use https://gitlab.com/groups/gitlab-org/-/epics/5672
-# To be removed https://gitlab.com/gitlab-org/gitlab/-/issues/335178
-class PropagateServiceTemplateWorker # rubocop:disable Scalability/IdempotentWorker
-  include ApplicationWorker
-
-  data_consistency :always
-
-  sidekiq_options retry: 3
-
-  feature_category :integrations
-
-  LEASE_TIMEOUT = 4.hours.to_i
-
-  def perform(template_id)
-    return unless try_obtain_lease_for(template_id)
-
-    ::Integrations::PropagateTemplateService.propagate(Integration.find_by_id(template_id))
-  end
-
-  private
-
-  def try_obtain_lease_for(template_id)
-    Gitlab::ExclusiveLease
-      .new("propagate_service_template_worker:#{template_id}", timeout: LEASE_TIMEOUT)
-      .try_obtain
-  end
-end

config/sidekiq_queues.yml

@@ -351,8 +351,6 @@
   - 1
 - - propagate_integration_project
   - 1
-- - propagate_service_template
-  - 1
 - - reactive_caching
   - 1
 - - rebase

db/post_migrate/20211103141403_remove_propagate_service_template_worker.rb

+# frozen_string_literal: true
+
+class RemovePropagateServiceTemplateWorker < Gitlab::Database::Migration[1.0]
+  def up
+    Sidekiq::Queue.new('propagate_service_template').clear
+  end
+
+  def down
+    # no-op
+  end
+end

db/schema_migrations/20211103141403

+d16d62b2984586540a99aa5fc67de6459a4cd473089ddbae8d45e8783863d78d
\ No newline at end of file

spec/workers/every_sidekiq_worker_spec.rb

@@ -398,7 +398,6 @@ RSpec.describe 'Every Sidekiq worker' do
         'PropagateIntegrationInheritWorker' => 3,
         'PropagateIntegrationProjectWorker' => 3,
         'PropagateIntegrationWorker' => 3,
-        'PropagateServiceTemplateWorker' => 3,
         'PurgeDependencyProxyCacheWorker' => 3,
         'ReactiveCachingWorker' => 3,
         'RebaseWorker' => 3,