codeintel: Refactor store
Created by: efritz
This removes the code that was moved from the code intel store into the workerutil store. This is a transitional step that will ensure we only have one active code path for this behavior. At the end of this refactor effort, there shouldn't be any "shim" layer in this store accessing/creating other layers (this is just the smallest diff to get this benefit).
This is part of https://github.com/sourcegraph/sourcegraph/issues/11786 and blocks https://github.com/sourcegraph/sourcegraph/pull/12262.