Add ci_secrets_management Premium feature

Add new Premium feature named `ci_secrets_management` and also add
project scoped feature flag named `ci_secrets_management_vault` to help
with rolloutt of Vault secrets support.

Related to https://gitlab.com/gitlab-org/gitlab/-/issues/28321
and https://gitlab.com/gitlab-org/gitlab/-/issues/218746.

ee/app/models/ee/ci/build.rb

@@ -134,6 +134,10 @@ module EE
         !merge_train_pipeline? && super
       end
 
+      def ci_secrets_management_available?
+        project.beta_feature_available?(:ci_secrets_management)
+      end
+
       private
 
       def parse_security_artifact_blob(security_report, blob)

ee/app/models/license.rb

@@ -52,6 +52,7 @@ class License < ApplicationRecord
     board_assignee_lists
     board_milestone_lists
     ci_cd_projects
+    ci_secrets_management
     cluster_deployments
     code_owner_approval_required
     commit_committer_check

ee/spec/models/ci/build_spec.rb

@@ -486,4 +486,24 @@ RSpec.describe Ci::Build do
       expect(described_class.license_scan).to contain_exactly(build_with_license_scan)
     end
   end
+
+  describe 'ci_secrets_management_available?' do
+    subject(:build) { job.ci_secrets_management_available? }
+
+    context 'when secrets management feature is available' do
+      before do
+        stub_licensed_features(ci_secrets_management: true)
+      end
+
+      it { is_expected.to be true }
+    end
+
+    context 'when secrets management feature is not available' do
+      before do
+        stub_licensed_features(ci_secrets_management: false)
+      end
+
+      it { is_expected.to be false }
+    end
+  end
 end