Restructure cloudmigration service (#83211)

* Restructure cloudmigation service

* Adjust codewoners and wire

* Comment out unused metrics

pkg/services/cloudmigration/cloudmigrations.go

@@ -0,0 +1,9 @@
+package cloudmigration
+
+import (
+	"context"
+)
+
+type Service interface {
+	MigrateDatasources(context.Context, *MigrateDatasourcesRequest) (*MigrateDatasourcesResponse, error)
+}