Existing Web IDE and `New` Web IDE should co-exist or opt-in status
Problem to solve
Rolling out a new Web IDE based on an additional compute requirement is complicated and many organizations may not want to upgrade to that immediately. However, we shouldn't restrict upgrades for the rest of GitLab because of this feature. We should allow the new IDE to be opt-in (toggle feature flag of old IDE off and new IDE on) for a period of XXX releases.