roadmap: mv align project to 3.0 release date

Created by: ggilmore

The vast majority of the work to migrate dogfood is done in https://github.com/sourcegraph/infrastructure/pull/699. It's being reviewed right now, but the physical migration (tear down old cluster, change DNS records, etc.), can't be completed until @chrismwendt's work is done that will allow Go code intelligence to be deployable without access to frontend's internal API.

I am starting work on prod now. I expect the bulk of the work (configuring deploy-sourcegraph repo fork, writing documentation) to be done before I am OOO on Wednesday. The physical migration of prod (snapshotting/migrating PVCs) should wait until I am back to supervise it.

I don't expect this project to slip into January, but it won't be entirely completed this week either.