Restructure cloudmigration service (#83211)

* Restructure cloudmigation service

* Adjust codewoners and wire

* Comment out unused metrics

pkg/services/cloudmigration/cloudmigrationimpl/cloudmigration_noop.go

@@ -0,0 +1,16 @@
+package cloudmigrationimpl
+
+import (
+	"context"
+
+	"github.com/grafana/grafana/pkg/services/cloudmigration"
+)
+
+// CloudMigrationsServiceImpl Define the Service Implementation.
+type NoopServiceImpl struct{}
+
+var _ cloudmigration.Service = (*NoopServiceImpl)(nil)
+
+func (s *NoopServiceImpl) MigrateDatasources(ctx context.Context, request *cloudmigration.MigrateDatasourcesRequest) (*cloudmigration.MigrateDatasourcesResponse, error) {
+	return nil, cloudmigration.ErrFeatureDisabledError
+}