RFC 629: Add object store sink for `lsif_indexes`

Created by: efritz

Implements a portion of RFC 629: Cold-storing older worker execution logs.

Update the log stasher instance created in #33030 to (optionally) use an instance of the object store sink introduced in #33028. This should add additional logic to the codeintel worker service initialization.

See #33033 for a possibly useful and/or blocking utility task.