Address out of memory errors when many features are enabled at the same time

Because all feature components are rebuilt in a single page load, enabling many features at once can lead to very slow page loads or out of memory errors. See #1332112: Install of Open Outreach hangs at last screen.

The issue is being worked on in #1572578: Rethink the way features are enabled / disabled. Meantime, a workaround is possible, based on an approach used in Commerce Kickstart.