Prepare projects and namespaces loose foreign keys

This commit adds post-migrations for tracking deletions of
namespaces and projects tables.

This commit did not include specs and foreign key definitions because
those tables are not available yet.

Changelog: other

db/post_migrate/20211130201100_track_deletions_in_namespaces.rb

+# frozen_string_literal: true
+
+class TrackDeletionsInNamespaces < Gitlab::Database::Migration[1.0]
+  include Gitlab::Database::MigrationHelpers::LooseForeignKeyHelpers
+
+  enable_lock_retries!
+
+  def up
+    track_record_deletions(:namespaces)
+  end
+
+  def down
+    untrack_record_deletions(:namespaces)
+  end
+end

db/post_migrate/20211130201101_track_deletions_in_projects.rb

+# frozen_string_literal: true
+
+class TrackDeletionsInProjects < Gitlab::Database::Migration[1.0]
+  include Gitlab::Database::MigrationHelpers::LooseForeignKeyHelpers
+
+  enable_lock_retries!
+
+  def up
+    track_record_deletions(:projects)
+  end
+
+  def down
+    untrack_record_deletions(:projects)
+  end
+end

db/schema_migrations/20211130201100

+cc0146769929c9fbb0b7b6788826d2e188c8664a14e1015563ba4f9e65397c4e
\ No newline at end of file

db/schema_migrations/20211130201101

+b0215ac45031593ca98de4f8858d21f1c29af03742a422bffd83598e39a6871c
\ No newline at end of file

db/structure.sql

@@ -28729,6 +28729,10 @@ CREATE TRIGGER ci_pipelines_loose_fk_trigger AFTER DELETE ON ci_pipelines REFERE
 
 CREATE TRIGGER ci_runners_loose_fk_trigger AFTER DELETE ON ci_runners REFERENCING OLD TABLE AS old_table FOR EACH STATEMENT EXECUTE FUNCTION insert_into_loose_foreign_keys_deleted_records();
 
+CREATE TRIGGER namespaces_loose_fk_trigger AFTER DELETE ON namespaces REFERENCING OLD TABLE AS old_table FOR EACH STATEMENT EXECUTE FUNCTION insert_into_loose_foreign_keys_deleted_records();
+
+CREATE TRIGGER projects_loose_fk_trigger AFTER DELETE ON projects REFERENCING OLD TABLE AS old_table FOR EACH STATEMENT EXECUTE FUNCTION insert_into_loose_foreign_keys_deleted_records();
+
 CREATE TRIGGER trigger_delete_project_namespace_on_project_delete AFTER DELETE ON projects FOR EACH ROW WHEN ((old.project_namespace_id IS NOT NULL)) EXECUTE FUNCTION delete_associated_project_namespace();
 
 CREATE TRIGGER trigger_has_external_issue_tracker_on_delete AFTER DELETE ON integrations FOR EACH ROW WHEN ((((old.category)::text = 'issue_tracker'::text) AND (old.active = true) AND (old.project_id IS NOT NULL))) EXECUTE FUNCTION set_has_external_issue_tracker();